CODEWITHSUNDEEP
c++multidimensional-array
eylay
eylay

Reputation: 2160

A function that creates two dimensional dynamic array

I wanted to create a function that creates a two dimensional dynamic array. so i wrote: 

#include<iostream>
using namespace std;

void make_mat (double *** , int, int);
int main(){
    int m = 3, n = 4;
    double **a;
    make_mat(&a,m,n);

    for (int i = 0; i < m; i++)
        for (int j = 0; j < m; j++)
            cin >> a[i][j];
    for (int i = 0; i < m; i++){
        for (int j = 0; j < m; j++)
            cout << a[i][j] << '\t';
        cout << endl;
    }
    return 0;
    system("pause");
}

void make_mat( double ***x , int m , int n){
    *x = new double *[m];
    for (int i = 0; i < m; i++){
        *x[i] = new double [n];
    }
}

There's no syntax errors in the codes but i get following error after compiling:

Unhandled exception at 0x003657E6 in ConsoleApplication20.exe: 0xC0000005: Access violation writing location 0xCCCCCCCC.

Totally this is not a good way for creating a function that creates two dimensional dynamic array. is there any better idea or any correction on the code above?

Upvotes: 0

Views: 53

Answers (1)

MikeCAT
MikeCAT

Reputation: 75062

*x[i] is equivalent to *(x[i]), which is equivalent to x[i][0].

You should use (*x)[i] instead of *x[i] in the function make_mat().

Upvotes: 2

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