function problems

[faxtoaster]

I need to write a program where i write a function to ask a user to input a number, then i need to write 3 other functions one multiplying it by 2, the other multiplying it by 3 and the other multiplying it by 4. All the while using only one variable name fVal. (This is to teach me to get used to the scope of variables). And I can only use fVal in the functions and the main program. I have tried over and over, but I always end up changing the value of fVal and i get fVal * 2 then that times 3 then that answer times 4. Which is wrong, please help! Thanks!

[mart_man00]

so this is wrong?

#include <stdio.h>

int get_number() {
    int number = 0;
    
    printf("enter a number\n");
    scanf("%d", &number);
    
    return number;
}

int by2(int number) {
    return (number * 2);
}

int by3(int number) {
    return (number * 3);
}

int by4(int number) {
    return (number * 4);
}

int main() {
    int fVal;
    
    fVal = get_number();
    fVal = by2(fVal);
    fVal = by3(fVal);
    fVal = by4(fVal);
    
    printf("\nfVal now equals %i\n", fVal);

    return 0;
}

you just want to print the changes and not keep them? then you could replace my returns with printfs. im not sure i get it.

<edit>
it took almost a full min for the submit button to actually submit.

[faxtoaster]

This is what I've tried. My only variable is fVal, and if I entered 5 for fVal when running the program i get this. fVal = 10, fVal = 30, fVal = 120. But it should be 10, 15, 20. See what I mean? If you have more help I'd appreciate it. Thanks!

#include <stdio.h>

float GetValue()
{   
    float fVal;
    printf("Enter a value for fVal: ");
    scanf("%f", &fVal); 
    return (fVal);	
}

void Compute1(float fVal)
{   
    
    fVal = fVal * 2;
    printf("fVal * 2: %f\n", fVal);
    
}

void Compute2(float fVal)
{
    
    fVal = fVal * 3;
    printf("fVal * 3: %f\n", fVal);
    
}

void Compute3(float fVal)
{
    
    fVal = fVal * 4;
    printf("fVal * 4: %f\n", fVal);
    
} 

int main(void)
{


float GetValue();
void Compute1 ();
void Compute2 ();
void Compute3 ();
 
   
    
     float fVal = GetValue();
     Compute1();
     Compute2();
     Compute3();

return(0);

}

[Zach L.]

Each of the ComputeX() functions takes a float argument, which you have not passed to it. Normally the compiler would complain, but you've also provided overloaded declarations inside main which do not take parameters.

int main(void)
{

     float fVal = GetValue();
     Compute1(fVal);
     Compute2(fVal);
     Compute3(fVal);

return(0);

}

[Slaught]

As easy as this, if I understood well:

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
int FVal;

printf("Input a number: ");
scanf("%d", &FVal);
printf("Number = %d \n Multiplied by two = %d \n Multiplied by three = %d \n Multiplied by four = %d \n", FVal, FVal*2, FVal*3, FVal*4);
system("PAUSE");
return 0;
}

it returns, for example, is you input "5":

Number = 5
Multiplied by two = 10
Multiplied by three = 15
Multiplied by four = 20

Pretty simple huh?

[faxtoaster]

thanks for all the help guys, i got it working, as usual it was a simple mistake i was making.