View Compilation Error

0_0_29463789_30303.cpp: In function 'int main()':
0_0_29463789_30303.cpp:4:26: error: 'scanf' was not declared in this scope
  while(scanf("%d%d",&n,&m)!=EOF)
                          ^
0_0_29463789_30303.cpp:4:29: error: 'EOF' was not declared in this scope
  while(scanf("%d%d",&n,&m)!=EOF)
                             ^
0_0_29463789_30303.cpp:7:28: error: 'printf' was not declared in this scope
      printf("%.2f\n",result);
                            ^