CODEWITHSUNDEEP
c++operator-overloadingflush
Sam Wilton
Sam Wilton

Reputation: 9

C++ flush() not working? Can't use endl

For a class assignment I have to overload the insertion and extraction operators. I'm having trouble getting it to print to the console.

EDITED

Sorry, this is my first time posting. I realize that I didn't post enough info for you guys, I have updated with what should be the necessary code

driver.cpp

#include "mystring.h"
#include <iostream>

using namespace std;

int main(){
    char c[6] = {'H', 'E', 'L', 'L', 'O'}
    MyString m(c);
    cout << m;

    return 0;
}

mystring.h

class MyString
{
  friend ostream& operator<<(ostream&, const MyString&);

  public:
    MyString(const char*);
    ~MyString(const MyString&)

  private:
    char * str;  //pointer to dynamic array of characters
    int length;  //Size of the string

  };

mystring.cpp

#include "mystring.h"
#include <iostream>
#include <cstring>

using namespace std;

MyString::MyString(const char* passedIn){
    length = strlen(passedIn)-1;
    str = new char[length+1];
    strcpy(str, passedIn);
}

MyString::~MyString(){
  if(str != NULL){
    delete [] str;
  }
}

ostream& operator << (ostream& o, const MyString& m){
  for(int i = 0; i < strlen(m.str); i++){
    o << m.str[i];
  }
  o.flush();
  return o;
}

Upvotes: 0

Views: 651

Answers (2)

Pete Becker
Pete Becker

Reputation: 76370

Don't try to flush from inside an inserter. None of the standard inserters does that. Just add std::cout << '\n'; after the call to your inserter in main.

The issue here is that std::cout is line buffered. That means it saves the inserted characters in an internal buffer until it sees a newline character (or until it's explicitly flushed). You'll see the same behavior if you insert a std::string object but don't end the line.

Upvotes: 1

GreatAndPowerfulOz
GreatAndPowerfulOz

Reputation: 1775

use the ostream::flush() method. As in:

ostream& operator << (ostream& o, const MyString& m){
    for(int i = 0; i < strlen(m.str)-1; i++){
        o << m.str[i];
    }
    o.flush();
    return o;
}

Upvotes: 1

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