working out the sum of integers

abdi_84 · 11-07-2009, 01:37 PM

hi
im working on an excercise which wants the user to input a number of the numbers to work out a sum of, and then to ask for each number in turn...

the program should print out the standard deviation, error in the mean sum of n numbers and sum of their squares.

this is what i have soo far.

Code:

#include <stdio.h>
int main(void);
     double i;  // variable for each number in turn
     char n;

        int s;  // sum
        int s2;// square of the sums
        int sdeviation;// standard deviation
        int error; // error in the mean

        printf("Write the number n of numbers: ");
        scanf("%c ", &n);

        for n>=0 {
            printf("Write each number in turn: ");
            scanf("%lf ", &i)
        }

        s = x++;  // this my code for the sum of n numbers
        
        s2 =(x*x)++; // the squares of the sum added together
        sdeviation = sqrt(u2 - (u*u)); // formula for standard deviation 
        error = sdeviation/sqrt(n); // formla for the error in the mean

i have a few errors, i just need a bit of direction on how to make my program work

any help is appreciated very much!

nadroj · 11-07-2009, 02:06 PM

Code:

int main(void);

You do not want a semi-colon here. "main" (in your case) should look like

Code:

int main(void)
{
  // stuff here
  return 0;
}

You dont have open or close brackets either.

Code:

for n>=0

Should be

Code:

for (n>=0) {

And a number of other errors. Though you should fix these, then read through the code to spot these errors.

Quote:

i have a few errors

Though we can probably figure out what the errors are, if you have some then: What are the errors?!

Adak · 11-07-2009, 02:06 PM

This program is badly messed up. You get the number n, and use it in a malformed for loop (with critical parts missing), to get the i variable, which is never used.

Then it starts referring to x, which is not even declared as a variable. Even your line declaring int main is defective, with a semi-colon, and no curly brace surrounding it's code.

Before you type up code, you need to go back and read your book. You have badly jumped ahead, and missed out on all the important basics.

You can't begin to salvage this code.

abdi_84 · 11-07-2009, 02:28 PM

Quote:

Originally Posted by Adak

This program is badly messed up. You get the number n, and use it in a malformed for loop (with critical parts missing), to get the i variable, which is never used.

Then it starts referring to x, which is not even declared as a variable. Even your line declaring int main is defective, with a semi-colon, and no curly brace surrounding it's code.

Before you type up code, you need to go back and read your book. You have badly jumped ahead, and missed out on all the important basics.

You can't begin to salvage this code.

alright

i've corrected the int main problem which was a typing error
the variable x is actually n, so i changed that

moving on

heres my malformed for loop..

Code:

for (n>=0) {
            printf("Write each number in turn: ");
            scanf("%lf ", &i)
        }

the aim of it is to perform a number of operations on each variable entered by the user, how do i achieve that?

nadroj · 11-07-2009, 02:31 PM

Cprogramming.com Tutorial: Loops
Also you could read other topics here Cprogramming.com - Programming Tutorials: C++ Made Easy and C Made Easy

abdi_84 · 11-07-2009, 02:38 PM

Quote:

Originally Posted by nadroj

Cprogramming.com Tutorial: Loops
Also you could read other topics here Cprogramming.com - Programming Tutorials: C++ Made Easy and C Made Easy

thanks i'll have a read

iMalc · 11-07-2009, 03:34 PM

May I suggest a change in your programming methodology please?

What you need to do is to start with a program that compiles. Basically start with the empty main program and compile that. Then as you go, add bits and compile again after every few lines you add. If something wont compile, fix the obvious bugs or undo your last changes until it compiles again. Don't add more until what you have already compiles. You shouldn't get as far as you have now without having compiled it successfully about 4 or 5 times (given your current ability level). On top of that, you should probably run your program after every few compiles as well, so that you know the code is doing what you intended it to.

That way you wont be stuck with code that has lots of problems and generates a ton of errors that you cannot solve.

Quote:

Originally Posted by nadroj

Code:

for (n>=0) {

No, that wont compile either. I think you're looking for a "while" loop there, but you also need to ensure it isn't an infinite loop as it would be now since n doesn't change in the loop.

nadroj · 11-07-2009, 03:40 PM

Quote:

No, that wont compile either. I think you're looking for a "while" loop there

Wow! Im new at this :s.

11-07-2009, 02:06 PM	#3
Adak Registered User Join Date: Sep 2006 Posts: 2,512	This program is badly messed up. You get the number n, and use it in a malformed for loop (with critical parts missing), to get the i variable, which is never used. Then it starts referring to x, which is not even declared as a variable. Even your line declaring int main is defective, with a semi-colon, and no curly brace surrounding it's code. Before you type up code, you need to go back and read your book. You have badly jumped ahead, and missed out on all the important basics. You can't begin to salvage this code.
Adak is offline

11-07-2009, 02:31 PM	#5
nadroj Registered User Join Date: Oct 2006 Location: Canada Posts: 848	Cprogramming.com Tutorial: Loops Also you could read other topics here Cprogramming.com - Programming Tutorials: C++ Made Easy and C Made Easy
nadroj is offline

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