#include <stdio.h>

void func() {
    static int x = 0; // x is initialized only once across three calls of func() and
                                 // the variable will get incremented three
                                 //times after these calls. The final value of x will be 3.
    printf("%d\n", x); // outputs the value of x
    x = x + 1;
}

int main() { //int argc, char *argv[] inside the main is optional in the particular program
    func(); // prints 0
    func(); // prints 1
    func(); // prints 2
    return 0;
}