Help with void functions

[alyssnyx]

This function is suppose to return 55 but every time I run it it says "The sum is 0". I have tried switching out the values in the void function, switching the loop to a for loop, and using return void () but nothing I do change the sum value. What am I doing wrong?

void compute_sum(int limit)  
{ 
   int sum = 0;
   int number = 1;

   while (number <= limit)
   { 
      sum += number;
      number++; 

   }
}

int main()
{ 
   int sum = 0;
   int limit = 10;

   compute_sum(limit);  
   cout << "The sum is " << sum << endl;
   
   return 0;
} 

[sky3]

Why dont you write this as a value returning function?

Also you cannot use return 0; in a void function. it does not return a value.

*either im crazy or sneaky edit e.e

[xismn]

@sky3

Also you cannot use return 0; in a void function. it does not return a value.

- Look again.

@alyssnyx
The problem is that in your compute_sum() function, you have a local variable named int sum, which is what ends up getting modified.
Then in main(), you have a variable with the same identifier and type, which you've initialized to zero, but never modify.

Fix this by either:
1.) As sky3 said, modify the function to return the sum.
2.)passing sum from main() by reference to compute_sum() and removing line 3.

[sky3]

this is super sloppy, but i got it working as value returning.

#include <iostream>

using namespace std;

int compute_sum(int number, int sum)  
{ 
    sum = 0;
   number = 1;
    int limit=10;


   while (number <= limit)
   { 
       sum = sum+ number;
      number++; 

   }
   return sum;
}


int main()
{ 
    
   int sum = 0;
  int  number = 1;
    int limit=10;
    cout << compute_sum(number,sum);

return 0;
}

[long double main]

You don't need that extra int sum parameter if you're returning the sum from the function. You really only need to make a few changes to the original code:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

int compute_sum(int limit) // 'void' --> 'int' { int sum = 0; int number = 1; while (number <= limit) { sum += number; number++; } return sum; // Return the sum here } int main() { int sum = 0; int limit = 10; sum = compute_sum(limit); // Assign the return value to 'sum' cout << "The sum is " << sum << endl; return 0; }

The sum is 55

[sky3]

I see! thanks.

[Garion]

You could still use a void function and get the proper result also.

What you would need is a pointer. This is how it looks with a pointer.

// Fun with pointers
#include <iostream>
using namespace std;

void compute_sum (int limit, int *psum)
{
  int sum = 0;
  int number = 1;
  while (number <= limit)
   {
      sum = sum+ number;
      number++;
    }
     *psum = sum;
}

int main ()
{
  int number = 10;
  int *a;
  compute_sum (number, a);
  cout << *a;
  return 0;
}

[alyssnyx]

Thanks for all the help! After reading the replies, switching the void to int seems to be simpler. Garion thanks for that pointer tip, I would use it but we haven't got to learn about that yet . Again thanks everyone for the help, I was stuck on this for hours.