View Compilation Error

0_0_30934307_20772.cpp: In function 'int main()':
0_0_30934307_20772.cpp:6:27: error: 'scanf' was not declared in this scope
   while(scanf("%d%d",&n,&m)!=EOF)
                           ^
0_0_30934307_20772.cpp:6:30: error: 'EOF' was not declared in this scope
   while(scanf("%d%d",&n,&m)!=EOF)
                              ^
0_0_30934307_20772.cpp:21:23: error: 'printf' was not declared in this scope
    printf("%.2lf\n",y1);
                       ^