View Compilation Error

0_0_36188631_28665.cpp: In function 'int main()':
0_0_36188631_28665.cpp:5:18: error: 'scanf' was not declared in this scope
    scanf("%d", &n);
                  ^
0_0_36188631_28665.cpp:9:26: error: 'printf' was not declared in this scope
        printf("%d\n", a+b);
                          ^