When i should use void for a function?

Question

When ishould use void for a function?..
What is its idea?

Answer 1

When you dont want to return a value you can use void function.
Here is a example for addition:

void sum(int a ,int b){
int sum = 0;
sum = a+b;
}
And then you can call the function but return function it will make easy.

int sum(int a ,int b){
return a+b;
}
And that's all.
Hope you understand!