View Compilation Error

0_0_15892102_18761.cpp:1:1: error: 'include' does not name a type
 include <stdio.h>
 ^
0_0_15892102_18761.cpp: In function 'int main()':
0_0_15892102_18761.cpp:10:41: error: 'scanf' was not declared in this scope
         scanf("%d%d%d%d", &a, &b, &s, &t);
                                         ^
0_0_15892102_18761.cpp:22:26: error: 'printf' was not declared in this scope
         printf("%dn", res);
                          ^