View Compilation Error

0_0_36020145_5951.cpp: In function 'int main(int, const char**)':
0_0_36020145_5951.cpp:4:29: error: 'scanf' was not declared in this scope
     while(scanf("%d%d",&a,&b)==2){
                             ^
0_0_36020145_5951.cpp:5:26: error: 'printf' was not declared in this scope
         printf("%d\n",a+b);
                          ^