View Compilation Error

0_0_27665601_17912.cpp: In function 'int main()':
0_0_27665601_17912.cpp:11:33: error: 'scanf' was not declared in this scope
        while(~scanf("%d%d",&b,&a)&&a+b){
                                 ^
0_0_27665601_17912.cpp:24:49: error: 'printf' was not declared in this scope
                  printf("%.1lf%%\n",(1-p[b])*100);}}
                                                 ^