Noob Help......Calculating volume and area of a sphere...

Hey guys,

I'm new to this language and am having a little problem getting the code below to run, its for a program this asks a user to enter a radius, and then computes the area and volume of a sphere...

any help would be greatly appreciated. Thanks :)

Code:

---


//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159

//FUNCTION PROTOTYPES
void explanation(void);
void volume_calc(void);
void printresults();

int main (void)
{
        explanation();//FUNCTION CALL
        volume_calc();//FUNCTION CALL
        printresults();

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
void volume_calc(void)
{
        //VARIABLE DECLARATIONS
        double radius, area, volume;
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        fflush (stdin);
        scanf ("%f", &radius);
        ;

        //CALCULATIONS
        volume=(4/3)*PI*(radius,3);
        area=4*PI*(radius,2);
       
        //OUTPUT
        printresults();
}
void printresults(float area, float radius, float volume)
{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\nthe area of this sphere is ==> %.3f", area);
}

---

These are the errors that are coming up....

Code:

---

1>LAB7A.obj : error LNK2019: unresolved external symbol "void __cdecl printresults(void)" (?printresults@@YAXXZ) referenced in function _main

1> : fatal error LNK1120: 1 unresolved externals

---

Notice that you called the printresults function without providing any arguments, but defined the function as having three parameters.

^^
hey yeah im noticing that now, i'm unsure of how to properly pass them though... :S

Thanks for the quick reply!

it just means you need to put (float area, float radius, float volume) in your protoype at the top, and when you call the function in your program it needs to have this amount of parameters too, but you only have to write in the names of the variables, not the type also, then in your actual function definition (where the work is done by the function) you need to show the arguments the same as you did in the prototyp, ie with the types also,

ps the actual variable names can be different there to reflect their exact use in the function itself if you like..

Quote:

---

Originally Posted by matt.s

^^
hey yeah im noticing that now, i'm unsure of how to properly pass them though... :S

Thanks for the quick reply!

---

Note that in volume_calc you are defining area, radius and volume as doubles, but your printresults function takes floats.

Anyway, to call printresults:

Code:

---

printresults(area, radius, volume);

---

^^
thank you, making a little sense now, i'll give it a go and post back! Thanks!

Quote:

---

Originally Posted by rogster001

it just means you need to put (float area, float radius, float volume) in your protoype at the top, and when you call the function in your program it needs to have this amount of parameters too, but you only have to write in the names of the variables, not the type also, then in your actual function definition (where the work is done by the function) you need to show the arguments the same as you did in the prototyp, ie with the types also,

ps the actual variable names can be different there to reflect their exact use in the function itself if you like..

---

You don't have to include the variable names in the function prototype, just the types:

Code:

---

void printresults(float, float, float);

---

gah... late again...

Okay so I've made the changes, and its compiling now :)
but it crashes when it gets to the 'printresults' function in main, saying that..

Code:

---

Run-Time Check Failure #3 - The variable 'radius' is being used without being initialized.

---

Heres the changes i've made so far......

Code:

---

/*
Title: Program to calculate the volume of two rooms
Author: Matthew Sokolowski 025 586 100 PRG 155
Date: February 21, 2010
Description: This program will use the function colume_calc()
                        to ask the user for l1,w1,h1 as well as l2, h2, w2
                        and then calculate the total volume.  This information
                        will then be passed to the screen by a function
*/

//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159

//FUNCTION PROTOTYPES
void explanation(void);
void volume_calc(void);
void printresults(double , double , double );

int main (void)
{
        double area, radius, volume;
        explanation();//FUNCTION CALL
        volume_calc();//FUNCTION CALL
        printresults(area, radius, volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
void volume_calc(void)
{
        //VARIABLE DECLARATIONS
        double radius, area, volume;
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        fflush (stdin);
        scanf ("%f", &radius);
        ;

        //CALCULATIONS
        volume=(4/3)*PI*(radius,3);
        area=4*PI*(radius,2);
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)
{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

Quote:

---

You don't have to include the variable names in the function prototype, just the types:

Code:
void printresults(float, float, float);

---

that is not good practice, bad advice

Quote:

---

Originally Posted by Epy

You don't have to include the variable names in the function prototype, just the types:

---

That is true, but normally you should include the parameter names in the prototype, to aid in readability.

Quote:

---

Originally Posted by matt.s

but it crashes when it gets to the 'printresults' function in main, saying that..

---

Yes. The problem is that the variables named area, radius, and volume in the main function are not related to the variables named radius, area, and volume in the volume_calc function.

What you can do is add parameters to the volume_calc function. These parameters will be pointers to the area, radius, and volume variables in the caller, i.e., the main function would pass the addresses of area, radius, and volume to volume_calc.

By the way, this results in undefined behaviour:

Code:

---

fflush(stdin);

---

Refer to this FAQ.

^^
sorta like this? passing radius, volume and area to the calculate function?

Code:

---

//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159

//FUNCTION PROTOTYPES
void explanation(void);
void volume_calc(void);
void printresults(double , double , double );

int main (void)
{
        double area, radius, volume;
        explanation();//FUNCTION CALL
        (area,radius,volume)volume_calc();//FUNCTION CALL
        printresults(area, radius, volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
(area,volume,radius)volume_calc(void)
{
        //VARIABLE DECLARATIONS
        double radius, area, volume;
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        scanf ("%f", &radius);
       

        //CALCULATIONS
        volume=(4/3)*PI*(radius,3);
        area=4*PI*(radius,2);
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)
{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

No, that does not make sense. I would expect something like this as the function call:

Code:

---

volume_calc(&area, &radius, &volume);

---

You would have to modify volume_calc accordingly to have pointer parameters.

sorta like this? sorry im so slow, i feel like such an idiot lol
but i really appreciate the help, im slowly seeing where i should be going with this...

Code:

---

//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159

//FUNCTION PROTOTYPES
void explanation(void);
void volume_calc(double area,double radius,double volume);
void printresults(double area, double radius, double volume);

int main (void)
{
       
        explanation();//FUNCTION CALL
        volume_calc(&area,&radius,&volume);//FUNCTION CALL
        printresults(area, radius, volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
void volume_calc(double area,double radius,double volume)
{
        //VARIABLE DECLARATIONS
        double radius, area, volume;
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        scanf ("%f", &radius);
       

        //CALCULATIONS
        volume=(4/3)*PI*(radius,3);
        area=4*PI*(radius,2);
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)
{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

Getting closer. volume_calc's parameters are still doubles rather than pointers to double. You should also remove those local variables from volume_calc, and since radius would then be a pointer to double, there would be no need to pass its address to scanf.

Okay, i made a couple changes, to try and pass the variables smoother, and it complies but I still get an error about it not being initilized correctly...is this starting to look a little better at least?

Code:

---


//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159

//FUNCTION PROTOTYPES

void explanation(void);
void volume_calc(double area, double radius,double volume);
void printresults(double area, double radius, double volume);

int main (void)
{
        double area, radius, volume;
        double a,r,v;
        area=a;
        radius=r;
        volume=v;
        explanation();//FUNCTION CALL
        volume_calc(a,r,v);//FUNCTION CALL
        printresults(area, radius, volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
void volume_calc( double a, double r,double v)
{
        //VARIABLE DECLARATIONS
        double radius, area, volume;
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        scanf ("%f", &radius);
       

        //CALCULATIONS
        volume=(4/3)*PI*(radius,3);
        area=4*PI*(radius,2);
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)
{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

What I mean is that this:

Code:

---

void volume_calc(double area, double radius,double volume);

---

should be:

Code:

---

void volume_calc(double *area, double *radius, double *volume);

---

Assigning to the local variables in volume_calc has no effect on the local variables in main. You need to assign to the local variables defined in main from within volume_calc, by having volume_calc operate on them via pointers.

By the way, you should also compile with a high warning level. The compiler should have been complaining to you that you were trying to pass pointers where they were not expected.

^^^
AHHHH! i see! :)

what does this refer to?

Code:

---

error C2440: '=' : cannot convert from 'double' to 'double *'

---

in regards to...

Code:

---

        volume=((4/3)*PI*(radius,3));
        area=(4*PI*(radius,2));

---

Quote:

---

Originally Posted by matt.s

what does this refer to?

---

Now that the parameters are pointers, you need to dereference them, i.e., *radius, *volume and *area.

clearly im missing something here because i still can't get it to run, perhaps i need to consider dropping this course lol

Code:

---


//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159

//FUNCTION PROTOTYPES

void explanation(void);
void volume_calc(double area, double radius,double volume);
void printresults(double area, double radius, double volume);

int main (void)
{
        double area, radius, volume;
        explanation();//FUNCTION CALL
        volume_calc(area,radius,volume);//FUNCTION CALL
        printresults(area, radius, volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
void volume_calc( double *area, double *radius, double *volume)
{
        //VARIABLE DECLARATIONS
       
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        scanf ("%f", &radius);
       

        //CALCULATIONS
        *volume=((4/3)*PI*(*radius,3));
        *area=(4*PI*(*radius,2));
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)
{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

Your volume_calc function's prototype does not match its definition, and when you call it in the main function, you did not pass pointers.

By the way, have you actually been taught how to use pointers?

unfortunatly my teacher is quite useless, and basically shows up to class late, throws on a video he found on youtube, and 15 mins later the class is over.

This is the first assignment we've had, and have barely even touched on functions so far, so this is a bit of a stretch for me right now.

any better?

Code:

---



//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159

//FUNCTION PROTOTYPES

void explanation(void);
double volume_calc(double *area, double *radius,double *volume);
void printresults(double area, double radius, double volume);

int main (void)
{
        double *area, *radius, *volume;
        explanation();//FUNCTION CALL
        volume_calc(area,radius, volume);//FUNCTION CALL
        printresults(*area, *radius, *volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
double volume_calc( double *area, double *radius, double *volume)
{
        //VARIABLE DECLARATIONS
       
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        scanf ("%f", &radius);
       

        //CALCULATIONS
        *volume=((4/3)*PI*(*radius,3));
        *area=(4*PI*(*radius,2));
        return (area,volume);
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)
{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

Almost there. Check what you are passing to volume_calc when you call it.

As laserlight pointed out, you are doing good, just double check the way you using pointers. Remember a pointer is AN ADDRESS (i.e. &(<type>) of a variable). (*ptr) is the value contained in the address pointed to by ptr.

Example:

Code:

---


int i_am_an_integer_value;
i_am_an_integer_value = 3;
int *i_am_a_pointer_to_an_int;
/* pointer (which is an address) is assigned address of int */
i_am_a_pointer_to_an_int = &i_am_an_integer_value;
/* value contained at address pointed to by the pointer is an int */
/* so *i_am_a_pointer_to_an_int is of type int and has the value 3 */

---

am i just going around in circles now?

Code:

---

//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159

//FUNCTION PROTOTYPES

void explanation(void);
double volume_calc(double area, double radius,double volume);
void printresults(double area, double radius, double volume);

int main (void)
{
        double area, radius, volume;
        explanation();//FUNCTION CALL
        volume_calc(area,radius,volume);//FUNCTION CALL
        printresults(area, radius, volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
double volume_calc( double area, double radius, double volume)
{
        //VARIABLE DECLARATIONS
       
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        scanf ("%f", &radius);
       

        //CALCULATIONS
        volume=((4/3)*PI*(radius,3));
        area=(4*PI*(radius,2));
        return (area,volume);
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)
{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

i keep getting

Code:

---

Run-Time Check Failure #3 - The variable 'volume' is being used without being initialized.

---

Quote:

---

Originally Posted by matt.s

am i just going around in circles now?

---

Yes. Using your code in post #23, replace this:

Code:

---

volume_calc(area,radius, volume);

---

with:

Code:

---

volume_calc(&area, &radius, &volume);

---

Now, search the Web for a tutorial on pointers in C to better understand what you have just been guided to do.

^^^^
THANK YOU! :) ahh i see now, i wasnt pointing the right way, so the compiler didnt know!

i'm still coming up with these errors...

Code:

---

1>c:\users\matthew\desktop\assignment.cpp(27) : error C2664: 'volume_calc' : cannot convert parameter 1 from 'double **' to 'double *'

1>        Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast

1>c:\users\matthew\desktop\assignment.cpp(55) : error C2440: 'return' : cannot convert from 'double *' to 'double'

---

You can make the return type of volume_calc be void. By the way, you are compiling as C++ instead of C; try using say, .c as the file extension.

Ahhh okay..
I renamed it as a ".c" and its running a little smoother i think, but im still coming up with errors :S

Code:

---

1>c:\users\matthew\desktop\assignment.c(28) : warning C4047: 'function' : 'double *' differs in levels of indirection from 'double **'
1>c:\users\matthew\desktop\assignment.c(28) : warning C4024: 'volume_calc' : different types for formal and actual parameter 1
1>c:\users\matthew\desktop\assignment.c(28) : warning C4047: 'function' : 'double *' differs in levels of indirection from 'double **'
1>c:\users\matthew\desktop\assignment.c(28) : warning C4024: 'volume_calc' : different types for formal and actual parameter 2
1>c:\users\matthew\desktop\assignment.c(28) : warning C4047: 'function' : 'double *' differs in levels of indirection from 'double **'
1>c:\users\matthew\desktop\assignment.c(28) : warning C4024: 'volume_calc' : different types for formal and actual parameter 3
1>c:\users\matthew\desktop\assignment.c(56) : error C2059: syntax error : ')'

---

Code:

---

//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159


//FUNCTION PROTOTYPES

void explanation(void);
void volume_calc(double *area, double *radius,double *volume);
void printresults(double area, double radius, double volume);

int main (void)
{
        double *area, *radius, *volume;
        explanation();//FUNCTION CALL
        volume_calc(&area, &radius, &volume);//FUNCTION CALL
        printresults(*area, *radius, *volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
void volume_calc( double *area, double *radius, double *volume)
{
        //VARIABLE DECLARATIONS
       
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        scanf ("%f", &radius);
       

        //CALCULATIONS
        *volume=((4/3)*PI*(*radius,3));
        *area=(4*PI*(*radius,2));
        return ();
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)
{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

Sorry, but I think that you really have to pause and read a tutorial on pointers. You need to understand how to work with pointers before you can proceed. At the moment, it looks like you have been making changes to your code without the faintest clue of why I have been suggesting what I have been suggesting.

EDIT:
Oh, I did not notice that in your post #23, you changed your correct line of code to:

Code:

---

double *area, *radius, *volume;

---

which is not correct. If area, radius and volume are pointers, what are they supposed to point to? Again, this means that you need to understand the concept of a pointer and how to use pointers effectively.

^^^
AHH! okay makes perfect sense, I corrected that and now the program compiles!! :) :)

im not getting the desired output though lol

if i enter a radius of 25, i should get a volume of 65449.847 and an area of 7853.982, instead i'm getting a volume of 9.425 and an area of 25.133 :S

is it because im not returning anything from the calc?

Code:

---

//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159


//FUNCTION PROTOTYPES

void explanation(void);
void volume_calc(double *area, double *radius,double *volume);
void printresults(double area, double radius, double volume);

int main (void)
{
        double area, radius, volume;
        explanation();//FUNCTION CALL
        volume_calc(&area, &radius, &volume);//FUNCTION CALL
        printresults(area, radius, volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
void volume_calc( double *area, double *radius, double *volume)
{
        //VARIABLE DECLARATIONS
       
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        scanf ("%f", &*radius);
       

        //CALCULATIONS
        *volume=((4/3)*PI*(radius,3));
        *area=(4*PI*(radius,2));
       
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)

{
        printf("You entered a radius of %.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

It's mainly because you have 4/3 when computing your volume. 4/3 is assumed by the compiler to be an integer division and the result is 1. What you probably want is a floating point result so just do 4.0/3.0 instead of 4/3.

^^^
yeah just noticed that, gave it a quick fix the numbers are a bit better, but still way off.....

for some reason the radius is coming up as -92556900000000000000.000 when i display it at the end....can't seem to figure this one out.. hmmmmm

Quote:

---

Originally Posted by matt.s

^^^
yeah just noticed that, gave it a quick fix the numbers are a bit better, but still way off.....

for some reason the radius is coming up as -92556900000000000000.000 when i display it at the end....can't seem to figure this one out.. hmmmmm

---

What exactly is (radius,2) and (radius,3)?

(radius,2) = radius squared
(radius,3) = radius cubed

or at least it does according to my teacher, who could very well be wrong lol

ummm... NO!

Just use radius*radius for radius^2 and radius*radius*radius. it's not like you are raising to the 100th power.

If you wanted to do that you would write x = pow(radius,100); pow is a function defined in math.h

^^^^^
ahhh i see what your saying their, my teacher has clearly lost the plot i think lol :P

ahhhhhh its still giving me the wrong output! how can such a simple little program be so confusing!?! :S

Code:

---


//INCLUDE SECTION
#include <stdio.h> //def's 4 printf, scanf, getchar, puts, gets, fflush
#include <conio.h> //def's for getch
#include <stdlib.h> //def's 4 system
#define PI 3.14159


//FUNCTION PROTOTYPES

void explanation(void);
void volume_calc(double *area, double *radius,double *volume);
void printresults(double area, double radius, double volume);

int main (void)
{
        double area, radius, volume;
        explanation();//FUNCTION CALL
        volume_calc(&area, &radius, &volume);//FUNCTION CALL
        printresults(area, radius, volume);

        printf("\n\t\t\tPRESS ANY KEY TO EXIT");
        _getch();
        return 0;
}

//FUNCTION DEFINITIONS
void explanation(void)
{
        system ("cls");
        puts ("This program will ask you to enter the RADIUS of a sphere...");
        puts ("and then calculate the volume and surface area...");

}
void volume_calc( double *area, double *radius, double *volume)
{
        //VARIABLE DECLARATIONS
       
        //GET USER INPUT
        printf ("\n\n\nPlease entert the radius of the sphere==> ");
        scanf ("%f", &*radius);
       

        //CALCULATIONS
        *volume=((4.0/3.0)*PI*(*radius*(*radius)*(*radius)));
        *area=(4.0*PI*(*radius*(*radius)));
       
       
       
        //OUTPUT
}       
void printresults(double area,double radius,double volume)

{
        printf("You entered a radius of %9.3f...", radius);
        printf("\nthe volume of this sphere is ==> %.3f", volume);
        printf("\n\ntthe area of this sphere is ==> %.3f", area);
}

---

What's the input and output now?

Input: 25

Output:
You entered a radius of -925596047186160310000000000000000000000000.000...
The Volume of the sphere is: -33164118186955090000000000000000000000000000.000.. ...
The Area of the sphere is: 10765953004987781000000000000000000000000000.000.. ..

Try printing %lf

^^
same output

kinda whack no? :S

scanf ("%lf", radius); <--- correct

You undo and do an indirect, which means you put neither. :) Also the %lf again for double.

Ohhhh i was doing the %lf in the wrong place! and your right, its working perfect now! Thank you so much, greatly appreciated!!!!

Nice catch! I didn't see that coming.