multiple errors while compiling simple hello world c++ program in g++ ubuntu

Question

below is my hello world program i have written in nano editor.

#include<iostream>
using namespace std;
int main
 {
   cout<< "Hello world";
   return 0;
 }

when i compiled it, i got these many errors.

ello.cpp:4:5: warning: extended initializer lists only available with -std=c++11 or -std=gnu++11 [enabled by default]
 int main
     ^
hello.cpp:6:22: error: expected ‘}’ before ‘;’ token
  cout<< "Hello world";
                      ^
hello.cpp:6:6: error: invalid user-defined conversion from ‘std::basic_ostream<char>’ to ‘int’ [-fpermissive]
  cout<< "Hello world";
      ^
In file included from /usr/include/c++/4.8/ios:44:0,
                 from /usr/include/c++/4.8/ostream:38,
                 from /usr/include/c++/4.8/iostream:39,
                 from hello.cpp:1:
/usr/include/c++/4.8/bits/basic_ios.h:115:7: note: candidate is: std::basic_ios<_CharT, _Traits>::operator void*() const [with _CharT = char; _Traits = std::char_traits<char>] <near match>
       operator void*() const
       ^
/usr/include/c++/4.8/bits/basic_ios.h:115:7: note:   no known conversion for implicit ‘this’ parameter from ‘void*’ to ‘int’
hello.cpp:7:2: error: expected unqualified-id before ‘return’
  return 0;
  ^
hello.cpp:8:2: error: expected declaration before ‘}’ token
  }

please help me.

You need to find a [beginners book](http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list) to read. — Some programmer dude, Apr 01 '16 at 13:48
C++ error messages are carefully engineered to cause maximum confusion for trivial mistakes. — molbdnilo, Apr 01 '16 at 13:54
Also, DO NOT include the entire `std` namespace. `std::cout` is a better way of writing — KR29, Apr 01 '16 at 13:59
thanks a lot guys :). can't believe i did such a silly mistake. — Umesh, Apr 01 '16 at 14:17

score 1 · Accepted Answer · edited Apr 01 '16 at 14:13

1

You missed the parentheses that mark main() as a function:

#include <iostream>

int main() {
    std::cout << "!!!Hello World!!!" << std::endl;
    return 0;
}

Note that it's much easier to understand namespaces if you explicitly use std::cout and std::endl rather than using the whole of namespace std (which can get you into confusion if you're not clear about what's going on). Alternatively, at least be clear about what you're using:

#include <iostream>

using std::cout;
using std::endl;

int main() {
    cout << "!!!Hello World!!!" << endl;
    return 0;
}

edited Apr 01 '16 at 14:13

Toby Speight

27,591
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answered Apr 01 '16 at 13:47

Mouaici_Med

390
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yep, okey thank you for your remark :) !! – Mouaici_Med Apr 01 '16 at 14:15

multiple errors while compiling simple hello world c++ program in g++ ubuntu

1 Answers1