Can you give an example Main function in Cpp?

Answer 1

The main function is the entry point of your application. The minimal main() function is as follows:

int main()

{

return( 0 );

}

Clearly this does nothing but return the value zero to the caller. However, it is important to note that the main() function must return an integer to the calling program -- even if only zero. The return value may be used to indicate an error condition, with zero indicating success, but can be used for any purpose -- or it may be ignored altogether by the caller. However it is not for you to decide how the return value is used, so long as you return something. A main() function that returns void is an invalid program (some compilers may permit it, but they break the C/C++ standard if they do).

An actual main() function will normally include one or more sequential statements or function calls, or an infinite loop with a conditional expression to exit the loop. An infinite loop may be contained in another function. The loop may be used to process a message queue, for instance, which determines the program's flow of control.

The following example demonstrates a simple program containing infinite loop within main() itself, generating random numbers between 1 and 100 (inclusive), exiting the loop when the number is 1. The return value is the number of loops that were executed.

#include

#include

int main()

{

srand(( unsigned ) time( NULL ));

unsigned int loops = 0;

while( ++loops )

{

int n = rand() % 100 + 1;

std::cout << "Number: " << n << std::endl;

if( n == 1 ) break; // exit loop if n is 1.

}

std::cout << "Loops: " << loops << std::endl;

return( loops ); // return number of loops to caller.

}