CODEWITHSUNDEEP
c++loops
Justin Yoder
Justin Yoder

Reputation: 537

Loop not working in C++

I have created a program that creates a file of the users name and then allows them to insert lines. I want to make it so that if they enter nothing (just pressing enter) it exits, but I have trouble figuring out what I'm doing wrong. Here is my code:

#include <iostream>
#include <fstream>

using namespace std;

int main(){
 char filename[20];
 char line[81];
 int X;
 cout<<"Welcome to a very primative word precessor"<<endl;
 cout<<"please enter a filename"<<endl;
 cin.getline(filename, 19);
 ofstream file_out(filename, ios::app);
 if (! file_out){
    cout<<"Cannot open "<<filename;
    cout<<"!!!"<<endl;
    return -1;
 }
 cout<<"File "<<filename;
 cout<<" was opened."<<endl;
     do {
  cout<<"Enter your notes here"<<endl;
  cin.getline(line, 80);
  file_out<<line<<endl;
  cout<<line<<endl;
 }
 while (! line);
 cout<<"last line"<<endl;
 file_out.close();
 return 0;
}

Upvotes: 2

Views: 213

Answers (2)

Xai
Xai

Reputation: 38

It's just your while condition that needs to be changed:

while (strlen(line) != 0);

Upvotes: 2

codaddict
codaddict

Reputation: 455380

The problem is with the way you are comparing line:

do {
    cout<<"Enter your notes here"<<endl;
    cin.getline(line, 80);
    ...
}
while (! line);
      ^^^^^^^

! line is same as line == 0. Now line is the address of the char array:

char line[81];

So that comparison is always false as line will always evaluate to true.

You need to change it to:

while (! strcmp(line,""));

and add a 

#include <cstring>

at the beginning.

Upvotes: 2

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