View Compilation Error

0_0_20799814_3737.cpp: In function 'int main()':
0_0_20799814_3737.cpp:3:32: error: 'printf' was not declared in this scope
   printf("Input 2 number(a b):");
                                ^
0_0_20799814_3737.cpp:4:24: error: 'scanf' was not declared in this scope
   scanf("%d %d", &a, &b);
                        ^