Declarations and Initializations - General Questions

What will be the output of the program?

#include <stdio.h>

int main(void) {
    int i = 3;
    int j = i * i + i;
    printf("%d\n", j);
    return 0;
}

What will be the output of the program?

#include <stdio.h>

int main(void) {
    int x = 'a' - 'A';
    printf("%d\n", x);
    return 0;
}

What is the scope of a global variable declared static in a file?

What will be the output of the program?

#include <stdio.h>

int main(void) {
    static int x;
    printf("%d\n", x);
    return 0;
}

Which of the following is a valid C identifier?