View Compilation Error

0_0_31968813_9357.cpp: In function 'int main()':
0_0_31968813_9357.cpp:6:21: error: 'scanf' was not declared in this scope
  while(scanf("%d",&n)&&n>0)
                     ^
0_0_31968813_9357.cpp:24:20: error: 'printf' was not declared in this scope
    if(j) printf(" ");
                    ^
0_0_31968813_9357.cpp:25:22: error: 'printf' was not declared in this scope
    printf("%d",num[j]); 
                      ^
0_0_31968813_9357.cpp:27:14: error: 'printf' was not declared in this scope
   printf("\n");
              ^