View Compilation Error

0_0_19150695_22974.cpp: In function 'int main()':
0_0_19150695_22974.cpp:5:15: error: 'scanf' was not declared in this scope
  scanf("%d",&n);
               ^
0_0_19150695_22974.cpp:6:10: error: 'getchar' was not declared in this scope
  getchar();
          ^
0_0_19150695_22974.cpp:9:9: error: 'gets' was not declared in this scope
   gets(a);
         ^
0_0_19150695_22974.cpp:10:26: error: 'strlen' was not declared in this scope
   for (int i=0;i<strlen(a);i++ )
                          ^
0_0_19150695_22974.cpp:13:24: error: 'printf' was not declared in this scope
     printf("%c",a[0]-32);
                        ^
0_0_19150695_22974.cpp:15:24: error: 'printf' was not declared in this scope
     printf("%c",a[i]-32);
                        ^
0_0_19150695_22974.cpp:17:14: error: 'printf' was not declared in this scope
   printf("\n");
              ^