View Compilation Error

0_0_36664239_32179.cpp: In function 'int main()':
0_0_36664239_32179.cpp:4:16: error: 'scanf' was not declared in this scope
  scanf("%d", &b);
                ^
0_0_36664239_32179.cpp:15:24: error: 'printf' was not declared in this scope
    printf("%d\n\n", sum);
                        ^
0_0_36664239_32179.cpp:17:22: error: 'printf' was not declared in this scope
    printf("%d\n", sum);
                      ^