Problems debugging simple console program :: CLion

Question

I am trying to learn basic C++ after being a Java developer. So I decided to give CLion a try. I wrote this basic code just to familiarize myself with some C++ syntax.

#include <iostream>
using namespace std;

int main() {
    string word;

    cout << "Enter a word to reverse characters: " << endl;
    getline(cin, word);

    for(int i = word.length(); i != -1; i--) {
        cout << word[i];
    }

    return 0;
}

The code is functional. It reverses whatever word you input. I wanted to step through it to see variables and what not, and to test out CLion's debugger.

My problem occurs when I get to

getline(cin, word);

When I step onto this line, I enter a word and hit enter. Then step over. After I do this nothing happens; all the step over, in, etc. buttons are disabled. I am unable to continue through the loop, or run the remainder of the code.

I have used Eclipse's debugger many times for Java development without any issues. Any ideas could be helpful.

TL;DR How do I step through a C++ command line program with basic input and output using CLion?

doesn't answer your question, but you've got undefined behavior: string word; char wordReversedArray[word.length()]; - you have an array with 0 length that you try to write into... — John3136
– John3136, Commented Oct 2, 2014 at 2:07
@John3136 You're correct. I changed the code to be a little more clear. The same problem still persists. — ryndshn
– ryndshn, Commented Oct 2, 2014 at 2:19
Could be as simple as buffering - cout << "str"; write to the console/terminal. The console can buffer things up until it gets a newline. Try cout << "str" << endl; too see if that explains things... — John3136
– John3136, Commented Oct 2, 2014 at 2:25
@John3136 That fixed one problem. It now prints when expected. However I'm still having the issue when inputting. — ryndshn
– ryndshn, Commented Oct 2, 2014 at 2:39
Add a cout before your loop to display the word. Add a cout in your loop to display i. See if eveything is as you expect. C++ uses 0 based indexes, so word[word.length] isn't valid. — John3136
– John3136, Commented Oct 2, 2014 at 2:46

sfjac · Accepted Answer · 2015-03-07 13:44:18Z

11

+50

I've replicated the problem - looks to me like when debugging the newline is being swallowed by the IDE and not passed back to the program. I've submitted a bug to JetBrains. I don't see a way to work around this aside from getting out of the IDE and debugging directly with GDB or another IDE.

UPDATE: This issue was fixed in the Clion EAP Build 140.1221.2. It even made the first change listed in the release notes:

The most valuable changes are:

Debugger doesn’t hang on ‘cin >>’ operator any more.

edited Mar 7, 2015 at 13:44

answered Nov 14, 2014 at 23:40

sfjac

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1 Comment

sfjac Over a year ago

Alas, this does not appear to have been fixed in the latest EAP.

CodeMonkey · Accepted Answer · 2014-11-12 22:41:01Z

1

Looking at your code, if everything is correct, you need to add #include <string>.

When I run this, it compiles and completes the output.

#include <iostream>
#include <string>

int main() {

    std::string word;

    std::cout << "Enter a word to reverse chars: ";
    std::getline(std::cin, word); //Hello

    for (int i = word.length() - 1; i != -1; i--) {
        //Without - 1 " olleh"
        //With    - 1 "olleh"
        std::cout << word[i];
    }
    std::cout << std::endl;
    system("pause");
    return 0;
}

edited Nov 12, 2014 at 22:41

answered Nov 12, 2014 at 22:28

CodeMonkey

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2 Comments

Mohit Jain Over a year ago

std::string on some C++ implementations may be available with iostream without including string explicitly. Moreover if std::string is unavailable, you would see a compile time error and not issue while debugging.

CodeMonkey Over a year ago

@MohitJain true, but with iostream, you call std::cin.getline(char*, streamsize). With string, you call std::getline(std::istream, std::string).

Naseef Chowdhury · Accepted Answer · 2014-11-14 05:39:16Z

1

Use the following code. I have modified your code to make it workable for your purpose. :)

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

int main() {
    string word;

    cout << "Enter a word to reverse characters: " << endl;
    getline(cin, word);

    for(int i = word.length() - 1; i != -1; i--) {
        cout << word[i];
    }

    printf("\n");

    system("pause");

    return 0;
}

answered Nov 14, 2014 at 5:39

Naseef Chowdhury

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2 Comments

user2913685 Over a year ago

Why are you saying it's ok to be using system("pause")? Don't you think that the beginner would benefit from some look into how to actually reverse a string in c++? string(s.rbegin(), s.rend()) implying s is a string?

Naseef Chowdhury Over a year ago

Actually don't understand what you are talking about. System("pause") actually able us to see the output window after execution of program completed. It has nothing to do with string reverse.

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