simple C++ question

itz2000 · 07-09-2006, 05:56 AM

What shall I do if I don't want to define string size?

i.e

Code:

#include <iostream>
#include <cstring>
using namespace std;

int main()
        {
                cout << "prints N times the message you want" << endl;
                int count=0;
                cout << "How much times do you want to write it?" << endl;
                cin >> count;
                cout << "What do you want to write?" << endl;
                char what[10];
                cin >> what;
                for (int i=0; i<=count; ++i) {
                                                cout << what << endl;
                                             }
                return 0;
        }

if I enter a string which is > 10, I create an overflow, that will cause unexpected results.
If I use char* pStr, it gets me segmantation fault, or maybe I've done this wrong?

suggestion?

Nylex · 07-09-2006, 06:07 AM

If you're using C++, why not just use the string class?

itz2000 · 07-09-2006, 06:09 AM

Quote:

Originally Posted by Nylex

If you're using C++, why not just use the string class?

can you write a small example?
I just don't find this in the book I got to learn the language.

Nylex · 07-09-2006, 06:19 AM

Certainly

. If you just want to read in a string with no spaces, e.g. just a word:

Code:

#include <iostream>
#include <string>

int main()
{
  string myString;
  cout << "Enter a word: ";
  cin >> myString;

  cout << "You entered: " << myString << endl;
  return 0;
}

If you want to enter a string that will contain spaces, like a sentence, you want to use getline instead:

Code:

cout << "Enter a string: ";
getline(cin, myString);

Which book are you using, by the way?

itz2000 · 07-09-2006, 06:33 AM

Quote:

Originally Posted by Nylex

Which book are you using, by the way?

add me on msn aitzk@hotmail.com

Ohh... and, Thanks!

[edit]
Is there any reason it doesn't work?

Code:

#include <iostream>
#include <cstring>
#include <string>
using namespace std;

int main()
        {
                cout << "prints N times the message you want" << endl;
                int count=0;
                cout << "How much times do you want to write it?" << endl;
                cin >> count;
                cout << "What do you want to write?" << endl;
                string myString;
                getline(cin,myString);
                for (int i=0; i<=count; ++i) {
                                                cout << myString << endl;
                                             }
                return 0;
        }

dmail · 07-09-2006, 11:11 AM

I know the reason, but for the life of me can't remember the work around. Whats happening is that you are reading from the standard input for the count and it leaves the newline '\n' on the standard input then when using getline it takes the newline off this is why you are not seeing anything.
I havn't got my books at hand at the minute, but I will have a little look around the net and post back.

[edit]
Didnt take long
after you call to read the count add
cin.ignore(1,'\n');
what this does is looks 1 characters in the standard input looking for a newline which it then disguards all the input upto and including the newline.

edited ignore.

itz2000 · 07-09-2006, 11:40 AM

Quote:

Originally Posted by dmail

I know the reason, but for the life of me can't remember the work around. Whats happening is that you are reading from the standard input for the count and it leaves the newline '\n' on the standard input then when using getline it takes the newline off this is why you are not seeing anything.
I havn't got my books at hand at the minute, but I will have a little look around the net and post back.

[edit]
Didnt take long
after you call to read the count add
cin.ignore(10,'\n');
what this does is looks 10 characters in the standard input looking for a newline which it then disguards all the input upto and including the newline. NOTE: 10 is just a randon number I used.

what is the new code then???