View Compilation Error

0_0_13405237_14023.cpp:1:1: error: 'include' does not name a type
 include <stdio.h>
 ^
0_0_13405237_14023.cpp: In function 'int main()':
0_0_13405237_14023.cpp:23:26: error: 'scanf' was not declared in this scope
  while(scanf("%d%d",&a,&b)==2){
                          ^
0_0_13405237_14023.cpp:25:31: error: 'is_prime' was not declared in this scope
    if(is_huiwen(i)&&is_prime(i))
                               ^
0_0_13405237_14023.cpp:26:19: error: 'printf' was not declared in this scope
     printf("%dn",i);
                   ^
0_0_13405237_14023.cpp:28:14: error: 'putchar' was not declared in this scope
   putchar('n');
              ^
0_0_13405237_14023.cpp: At global scope:
0_0_13405237_14023.cpp:32:1: error: expected unqualified-id before '--' token
 ----------------------------------------------------------------------------------
 ^