View Compilation Error

0_0_19354759_2474.cpp: In function 'int main()':
0_0_19354759_2474.cpp:4:24: error: 'scanf' was not declared in this scope
     scanf("%d %d",&a,&b);
                        ^
0_0_19354759_2474.cpp:5:20: error: 'printf' was not declared in this scope
     printf("%d",a+b);
                    ^