View Compilation Error

0_0_18506193_2081.cpp: In function 'int main()':
0_0_18506193_2081.cpp:3:26: error: 'scanf' was not declared in this scope
 while(scanf("%d %d",&a,&b)!=-1&&a!=0&&b!=0){
                          ^
0_0_18506193_2081.cpp:5:20: error: 'printf' was not declared in this scope
     printf("%d\n",c);
                    ^