#include <stdio.h>

void printX(int x) {  // x is an argument   (sometimes called a parameter)

    printf("%d\n", x);  // '\n'  ==>  10;  just like 'A'  goes to 65
                        //  \ is special to compiler.  % mostly is not in a string.
}

int main(int argc, const char *argv[])
{
    int a = 5;   // a is a "local variable"
    printX(a);
    return 0;
}