View Compilation Error

0_0_22117899_21526.cpp: In function 'int main()':
0_0_22117899_21526.cpp:6:23: error: 'scanf' was not declared in this scope
     scanf("%d%d",&a,&b);
                       ^
0_0_22117899_21526.cpp:7:22: error: 'printf' was not declared in this scope
     printf("%d\n",a+b);
                      ^