View Compilation Error

0_0_18712448_30649.cpp: In function 'int main()':
0_0_18712448_30649.cpp:5:2: error: 'cin' was not declared in this scope
  cin>>a>>b>>c>>d;
  ^
0_0_18712448_30649.cpp:6:32: error: 'sqrt' was not declared in this scope
  e=sqrt((a-c)*(a-c)+(b-d)*(b-d));
                                ^
0_0_18712448_30649.cpp:7:2: error: 'cout' was not declared in this scope
  cout<<setiosflags(ios::fixed)<<setprecision(2);
  ^
0_0_18712448_30649.cpp:7:20: error: 'ios' has not been declared
  cout<<setiosflags(ios::fixed)<<setprecision(2);
                    ^
0_0_18712448_30649.cpp:7:30: error: 'setiosflags' was not declared in this scope
  cout<<setiosflags(ios::fixed)<<setprecision(2);
                              ^
0_0_18712448_30649.cpp:7:47: error: 'setprecision' was not declared in this scope
  cout<<setiosflags(ios::fixed)<<setprecision(2);
                                               ^
0_0_18712448_30649.cpp:8:11: error: 'endl' was not declared in this scope
  cout<<e<<endl;
           ^