View Compilation Error

0_0_31051522_26174.cpp: In function 'int main()':
0_0_31051522_26174.cpp:7:21: error: 'scanf' was not declared in this scope
  scanf("%d %d",&n,&m); 
                     ^
0_0_31051522_26174.cpp:22:29: error: 'printf' was not declared in this scope
   printf("%.2f",(float)sum/n);
                             ^
0_0_31051522_26174.cpp:36:31: error: 'printf' was not declared in this scope
   printf("%.2f",(float)(sum)/m);
                               ^
0_0_31051522_26174.cpp:42:37: error: 'printf' was not declared in this scope
  printf("%d",numbersOfPassedStudents);
                                     ^