View Compilation Error

0_0_15534544_14718.cpp: In function 'int main()':
0_0_15534544_14718.cpp:5:22: error: 'scanf' was not declared in this scope
  while(scanf("%lf",&a)!=EOF)
                      ^
0_0_15534544_14718.cpp:5:25: error: 'EOF' was not declared in this scope
  while(scanf("%lf",&a)!=EOF)
                         ^
0_0_15534544_14718.cpp:8:20: error: 'printf' was not declared in this scope
  printf("%.2lf\n",b);}
                    ^