main() in C / C ++What should it return?

main()The return value of the function shows how the program exits. The normal exit of the program is represented by a return value of zero. If there are errors, faults, etc., it will terminate with a non-zero value.

In C ++In the language, themain()Functions can be retained without returning a value. By default, it will return zero.

This ismain()The syntax of functions in C language

int main() {
　　　...
　　　return 0;
}

This ismain()Function example in C language

Example

#include <stdio.h>
int main() {
　　　int a =　10;
　　　char b = 'S';
　　　float c =　2.88;
　　　a = a+b;
　　　printf("Implicit conversion from character to integer: %d\n", a);
　　　c = c+a;
　　　printf("Implicit conversion from integer to float: %f\n", c);
　　　return 0;
}

Output result

Implicit conversion from character to integer:　93
Implicit conversion from integer to float:　95.879997

In the above program, the main function contains the business logic. There are three variables a, b, and c, where a keeps the sum of a and b. Variable c contains the sum of c and a. The main function returns 0.

a = a+b;
printf("Implicit conversion from character to integer: %d\n", a);
c = c+a;
printf("Implicit conversion from integer to float: %f\n", c);
return 0;