View Compilation Error

0_0_36645481_25128.cpp: In function 'int main()':
0_0_36645481_25128.cpp:7:28: error: 'scanf' was not declared in this scope
         scanf("%d %d", a, b);
                            ^
0_0_36645481_25128.cpp:8:29: error: 'printf' was not declared in this scope
         printf("%d\n", a + b);
                             ^