View Compilation Error

0_0_29761591_31598.cpp: In function 'int main()':
0_0_29761591_31598.cpp:6:23: error: 'scanf' was not declared in this scope
    scanf("%d %d",&a,&b);
                       ^
0_0_29761591_31598.cpp:7:19: error: 'printf' was not declared in this scope
    printf("%d",a+b);
                   ^