Significance of main() function

main() is the function where every C program begins execution.

• The operating system calls main() at the start; the program ends when main() returns.
• Every program must have exactly one main() function.
• It contains (or calls) all the statements and functions of the program, so it controls the program flow.
• It returns an integer to the operating system: return 0; means successful execution, a non-zero value means an error.
• It can receive command-line arguments through int main(int argc, char *argv[]).

#include <stdio.h>
int main(void)
{
    printf("Program starts here\n");
    return 0;   /* 0 tells the operating system the program ended normally */
}

Output:

Program starts here