View Compilation Error

0_0_38517245_20396.cpp: In function 'int main()':
0_0_38517245_20396.cpp:4:21: error: 'scanf' was not declared in this scope
  while(scanf("%d",&a)!=EOF)
                     ^
0_0_38517245_20396.cpp:4:24: error: 'EOF' was not declared in this scope
  while(scanf("%d",&a)!=EOF)
                        ^
0_0_38517245_20396.cpp:8:23: error: 'printf' was not declared in this scope
    printf("%d: no\n",a);
                       ^
0_0_38517245_20396.cpp:16:32: error: 'printf' was not declared in this scope
    if(num>2)printf("%d: no\n",a);
                                ^
0_0_38517245_20396.cpp:17:29: error: 'printf' was not declared in this scope
    else printf("%d: yes\n",a);
                             ^