function prototype

I am a beginner in C++.I need to project the sum but it will not project. Please help.

 ``1234567891011121314151617181920212223242526`` `````` #include using namespace std; //function prototype void calcSum(int &n1, int &n2, int &n3); int main() { int num1 = 0; int num2 = 0; int num3 = 0; cout << "Enter the first number: "; cin >> num1; cout << "Enter the second number: "; cin >> num2; return 0; } //end of main function //*****function definitions***** void calcSum(int &n1, int &n2, int &n3) { n3 = n1 + n2; cout << "Sum: " << n3 << endl; }//end of calcSum function ``````
you did not actually CALL the function. you must call it!

 ``1234567891011121314`` `````` int main() { int num1 = 0; int num2 = 0; int num3 = 0; cout << "Enter the first number: "; cin >> num1; cout << "Enter the second number: "; cin >> num2; calcSum(num1, num2, num3); return 0; }``````

as a side note this is a bit odd.
most would do one of 3 things here.

int calcSum(int a, int b) //calculates and returns, letting main decide to print or use it..
{
return a+b;
}
//in main, num3 = calcSum(num1, num2);

or maybe this, removing the somewhat useless 3rd input, printing it here
void calcSum(int a, int b)
{
cout << a+b<< endl;
}

and a somewhat strange 3rd option (return in c, main handles result)

void calcSum(int a, int b, int &c)
{
c = a+b;
}

Nothing you have is wrong, beyond forgetting to call it.

Thank you, i have corrected and it worked.

 ``1234567891011121314151617181920212223242526`` ``````#include using namespace std; //function prototype void calcSum(int &n1, int &n2, int &n3); int main() { int num1 = 0; int num2 = 0; int num3 = 0; cout << "Enter the first number: "; cin >> num1; cout << "Enter the second number: "; cin >> num2; calcSum(num1, num2, num3); return 0; } //end of main function //*****function definitions***** void calcSum(int &n1, int &n2, int &n3) { n3 = n1 + n2; cout << "Sum: " << n3 << endl; }//end of calcSum function ``````
So... since you didn't address jonnin's issues, I'll ask the obvious question:

Why are you passing n1 and n2 into calcSum by reference?
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