#include<cstdio>

main() {

 int x = 4;

 printf("Value of x is: %d\n", x);
 if (x)
   printf ("x must be true\n");
 else
   printf ("x must be false\n");


 printf("By using ! before x, value is: %d\n", !x);
 if (!x)
   printf ("!x must be true\n");
 else
   printf ("!x must be false\n");

 printf("By using !! before x, value is: %d\n", !!x);
 if (!!x)
   printf ("!!x must be true\n");
 else
   printf ("!!x must be false\n");



}