typecasting int [n][m] to int ** gives segmentation fault

Asked Sep 25 '15 at 09:51

Active Sep 25 '15 at 10:17

Viewed 70 times

Why does this code give a segmentation fault:

int n, m;
cin >> n >> m;
int a[n][m];
for(int i = 0; i < n; i++)
    for(int j = 0; j < m; j++)
        cin >> a[i][j];

int ** x = (int **) a;

for(int i = 0; i < n; i++) {
    for(int j = 0; j < m; j++) {
        cout << x[i][j] << ' ';
    }
    cout << endl;
}

I'm using g++ 4.9.2 on Ubuntu.

edited Sep 25 '15 at 10:17

Klas Lindbäck

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asked Sep 25 '15 at 09:51

vantony

1

Read this http://stackoverflow.com/questions/7586702/is-2d-array-a-double-pointer – mathematician1975 Sep 25 '15 at 09:56
`int a[n][m]` is of type `int[][m]` which is different from `int**`. – Klas Lindbäck Sep 25 '15 at 10:00
@KlasLindbäck Actually, the code isn't standard C++ anyway, so it is hard to say what the type of `int[n][m]` is. – juanchopanza Sep 25 '15 at 10:06
Actually, I was looking in the C tag, so I assumed C. I'm removing the C tag since the code is clearly C++. – Klas Lindbäck Sep 25 '15 at 10:17

typecasting int [n][m] to int ** gives segmentation fault

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