Uninitialised local variable from class

Question

When I'm trying to access classes public variable (in this case trying to input text row) it shows that it's uninitialized. However, I declared it in class as a public variable. I know that's some dummy mistake, but can't find it :D

#include <iostream>
#include <conio.h>

using namespace std;

class stringlength {
private:
    int lengt;
public:
    char * row;

    int len()
    {
        for (int i = 0, lengt = 0; (*(row + i) != '\0'); i++, lengt++) {}
        return lengt;
    }
};
int main()
{
    stringlength test;

    cout << "Enter a string:";
    cin >> test.row;
    cout << "Length is: " << test.len();
    _getch();

}

This program is expected to give a length of the inputted row (like strlen function) Error is:

Error C4700 uninitialized local variable 'test' used

Thanks for help ;)

Not only do you need to initialise row, you also need to allocate some memory to store the string in. Have a look at the list of good books. — molbdnilo
– molbdnilo, Commented Apr 18, 2019 at 7:08
Naive question, why don't you use a std::string ? It's easier to use and harder to miss use. And it's have a .size() — Martin Morterol
– Martin Morterol, Commented Apr 18, 2019 at 7:23
As @molbdnilo say, you need to initialise row . stackoverflow.com/questions/15319690/char-and-cin-in-c may help — Martin Morterol
– Martin Morterol, Commented Apr 18, 2019 at 7:30
Take a look at stackoverflow.com/questions/15131772/assigning-cin-to-variables — eMazarakis
– eMazarakis, Commented Apr 18, 2019 at 8:44
std::string is easy. Yep :D But the task is about using a pointers to find the length — Raicha
– Raicha, Commented Apr 18, 2019 at 9:16

Michael Chourdakis · Accepted Answer · 2019-04-19 11:54:35Z

3

Declaring the variable does not mean that it's initialized.

Initialize it in a constructor, or just char * row = nullptr; (if 0 is the intended initialization).

Same for all the variables that you have which have no constructors.

Edit: in this specific case you need to initialize to a new pointer char * row = new char[...]

edited Apr 19, 2019 at 11:54

answered Apr 18, 2019 at 6:59

Michael Chourdakis

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2 Comments

Raicha Over a year ago

But I'm inputting it through cin. It seems a bit strange to me.

Raicha Over a year ago

Initialising it as array helped. ``` char * row = new row [4096] ```

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