Why is my function not Working??What am I doing wrong?

Question

#include <iostream>

using namespace std;

int main()
{
SUM();
cout << a << endl;
return 0;
}
int SUM()
{
int x=3;
int y=4;
int a=x+y;
cout <<"The sum is:"<<a<<endl;

}

Can you guys tell me why this function dosent work?

Answer 1

also the frist line of should be
int a = SUM();
not SUM();

Answer 2

you need to add this code
return x+y;
in the function
and delete the last 2 lines of code

Answer 3

since the function protype is int SUM();
that means the function will be returning a integer

Answer 4

that is why you need the return statement

if you dont want to return nothing replace int with void then you dont need the return statement

Answer 5

😏just take int a
because it is missing

other all right

Answer 6

also add this line of code
int SUM();
under using namespce std;

Answer 7

i never said you cant put cout in your function.

you could if you want .

Answer 8

Chris, can you explain me why it is necessary to put a return value and what does it do?Till now I dont understand what is value and what it does.An can you explain me why can I not put a cout instead of return?

Answer 9

Everything chris said
+
You need a prototype above main, because it does not know what SUM is.

Just put this above main:
int SUM();

alternatively you can put the function itself above main.

Answer 10

can u explain what is return on C++?And why cant I put cout instead of return?