void means function doesn't return any value?the program below return value of c?how

[shivani284]

void main()
{
int a=5, b=6,c;
c=a+b;
printf("%d",c);
getch();
}

[Banfa]

void main()

is undefined behaviour, it should be

int main()

Undefined behaviour means just that, the behaviour of the program is undefined it may do anything including what you describe.

You should avoid undefined behaviour.

[weaknessforcats]

This program does not return a value. c is a local variable and the function displays the local variable. There is no return statement in the function. If there were, the function would not compile with a void return type.

BTW: Banfa is correct in not using void main().

[donbock]

How does the OP know the return value of main is character c? Its not like some other function called main and received a return value.

The return value for function main is a special case. It isn't returned to the C function that called main; instead it is returned to the operating system environment that ran the program. I suspect the OP noticed that the operating system was getting a return value from the program that matched the value of c.

Function main is a special case for another reason. You don't write a function prototype for it. Instead, the function prototype is provided implicitly by the compiler. Regardless of whether your implementation of main returns a value, the C run-time environment knows there is a return value because of this implicit prototype.

Integer return values are frequently implemented by returning the value in a particular register. Thus, the C run-time environment is confident that the value of that register is whatever is in that register. Since you coded main without a return statement, the register holds some intermediate value ... as luck would have it, that intermediate value happens to be the value of c.