Code can run but doesn't show the Result in Eclipse.?

Question

Why the example code below can run fine on Visual Studio. In Eclipse, NetBean or CodeBlock the code can run but can't show the Result? Thanks All. Ex: input one string. a/ Uppercase first letter. b/ Remove spaces inside the string.

#include "iostream"
    #include "string.h"
    using namespace std;

    #define MAX 255

    //uppercase first letter
    char* Upper(char* input)
    {
        char* output = new char[MAX];

        bool isSpace = false;
        for (int i = 0; i < strlen(input); i++)
        {
            output[i] = input[i];
            if (isSpace)
            {
                output[i] = toupper(output[i]);
                isSpace = false;
            }
            if (output[i] == ' ') isSpace = true;
        }
        output[strlen(input)] = '\0'; // end of the string
        output[0] = toupper(output[0]); // first character to upper

        return output;
    }
    //remove space inside the string
    char* RemoveSpaceInside(char* input)
    {
        char* output = new char[MAX];
        strcpy(output, input);

        int countWhiteSpace = 0;
        for (int i = 0; i < strlen(output); i++)
        {
            if (output[i] == ' ')
            {
                for (int j = i; j < strlen(output) - 1; j++) // move before
                {
                    output[j] = output[j + 1];
                }
                countWhiteSpace++;
            }
        }
        output[strlen(output) - countWhiteSpace] = '\0'; // end of the string

        return output;
    }

    int main()
    {
        char* name = new char[MAX];
        cout << "Enter name: "; cin.getline(name, strlen(name)); 
        cout << "Your name: " << name << endl;

        cout << "\n******* Q.A *******\n";
        char* qa  = Format2VN(name);
        cout <<  qa << endl;

        cout << "\n******* Q.B *******\n";
        char* qb = RemoveSpaceInside(name);
        cout << qb << endl;
        return 0;
    }

That's some awful code you got there. I suggest you get your hands on a [good C++ book](http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list) ASAP. — Etienne de Martel, Jul 25 '12 at 18:51

score 2 · Accepted Answer · edited May 23 '17 at 10:24

char* name = new char[MAX];
cout << "Enter name: ";
cin.getline(name, strlen(name));

Calling strlen(name) will invoke undefined behavior, because you haven't initialized the array. Poor strlen will try to find the NUL character in an uninitialized byte mess. Definitely not a good idea.

What you probably want is:

cin.getline(name, MAX);   // not sure if MAX or MAX-1 or whatever

In general, do yourself a favor and replace char* with std::string. Also, get a good C++ book.

Here is how your example would look like in actual C++:

#include <algorithm>
#include <cctype>
#include <iostream>
#include <string>

std::string upper_first_letter(std::string s)
{
    if (!s.empty()) s[0] = toupper(s[0]);
    return s;
}

std::string remove_spaces(std::string s)
{
    s.erase(std::remove_if(s.begin(), s.end(), isspace), s.end());
    return s;
}

int main()
{
    std::string name;
    std::cout << "Enter name: ";
    std::getline(std::cin, name);

    std::cout << name << '\n';
    std::cout << upper_first_letter(name) << '\n';
    std::cout << remove_spaces(name) << '\n';
}

Code can run but doesn't show the Result in Eclipse.?

1 Answers1