Dynamic array allocation problem

[bheadmaster]

Hey guys. I'm having a problem with dynamic strings.
This is my code for entering words into an array of strings called "table":

#include <iostream>
#include <cstring>

using namespace std;


int main()
{
    char **table;
    int *length;    //pointer to an array in which the word lengths will be placed
    int nof_words;

    cout << "Enter the number of words: ";
    cin >> nof_words;

    table = new char*[nof_words];
    length = new int[nof_words];

    for(int i = 0, temp; i < nof_words; i++){  //this loop is a system which
                                               //enters words into a "table"
        cout << "Enter the length of a " << i + 1 << ". word: ";
        cin >> temp;
        if(temp){
            length[i] = temp;
            table[i] = new char[temp];
            cout << "Enter the word: ";
            char word[temp + 1];
            cin >> word;
            while(strlen(word) > (unsigned)temp){
                cout << "Word is too long, try again: ";
                cin >> word;
            }
            table[i] = word;
        }
    }

    for(int i = 0; i < nof_words; i++)
        cout << table[i] << endl;


    delete [] table;
    for(int i = 0; i < nof_words; i++)
        delete [] table[i];
    delete [] length;

    return 0;
}

However, whatever words I enter I always get some wild output such as:

'xG
'xG
'xG

What gives?

[anup30]

#include <iostream>
#include <cstring>

using namespace std;


int main()
{
    char **table;
    int *length;    //pointer to an array in which the word lengths will be placed
    int nof_words;

    cout << "Enter the number of words: ";
    cin >> nof_words;

    table = new char*[nof_words];
    //length = new int[nof_words]; ///not required!

    for(int i = 0, temp; i < nof_words; i++){  //this loop is a system which
                                               //enters words into a "table"
        cout << "Enter the length of word no. " << i + 1 << ": ";
        cin >> temp;
        if(temp>0){ /// >0
            //length[i] = temp;
            table[i] = new char[temp+1]; // temp+1
            cout << "Enter the word: ";
			cin >> table[i]; ////// use a loop (or getline) for not overflowing 
            /*char word[temp + 1];
            cin >> word; /// how long will it take ?? overflow may occur!
            while(strlen(word) > (unsigned)temp){
                cout << "Word is too long, try again: ";
                cin >> word;
            }
            table[i] = word;*/
        }
    }

    for(int i = 0; i < nof_words; i++)
        cout << table[i] << endl;


    //delete [] table; //not here
    for(int i = 0; i < nof_words; i++)
        delete [] table[i];
	delete [] table; //here
    //delete [] length;

    return 0;
}

[bheadmaster]

Thank you kind sir. =)


Line 17:

Why is it not requied? How else does a program know how many ints I'm gonna store? Wouldn't some problems eventually occur?

[anup30]

your program works without "length" variable.
you are providing char array dynamic size by "temp+1"
a

'\0'

is automatically appended after all words.


in your code you used

for(int i = 0; i < nof_words; i++)
        cout << table[i] << endl;

to print the words. without mentioning "length" variable.
so how the program knows where to stop ?

and if you enter a word of lesser length - it still works!

EDIT: be careful of line 28 cin >> word;, extra length can corrupt your system !!

[bheadmaster]

Ah, I see. I must have forgot what I wanted to use the "length" variable for.

Thank you for help!