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copied!<p>Couple things:</p> <ul> <li>You need to pass the argument by reference in func: <code>void func(int ***arr) {</code></li> <li>Then change the way you free things: <code>free((*arr)[i]);</code> and <code>free(*arr);</code></li> <li>and finally change how you reassign arr: <code>*arr = destMatrix;</code></li> <li>also, don't name variables starting with a number -- it doesn't work.</li> <li>(also, you had <code>++i</code> instead of <code>i++</code> at the for loop at the end of func ) this doesn't actually matter -- see the comment below</li> </ul> <p>I debugged these issues using <a href="http://valgrind.org/docs/manual/quick-start.html#quick-start.intro" rel="nofollow" title="Valgrind">Valgrind</a>, check it out.</p> <p>Working code is below:</p> <pre><code>#include <stdio.h> #include <stdlib.h> #define N 10 ////////////////////////////////////////////////////////////////////////// void func(int ***arr) { int **destMatrix = NULL; destMatrix = malloc(N * sizeof(int *)); if ((destMatrix == NULL)) { fprintf(stderr, "out of memory\n"); exit(2); } int i; for (i = 0; i < N; i++) { destMatrix[i] = malloc(N * sizeof(int)); if (destMatrix[i] == NULL) { fprintf(stderr, "out of memory\n"); exit(2); } } for(i = 0; i < N; i++) { free((*arr)[i]); } free(*arr); *arr = destMatrix; } ////////////////////////////////////////////////////////////////////////// int main() { int **tdArr = malloc(N * sizeof(int *)); if (tdArr== NULL) { fprintf(stderr, "out of memory\n"); exit(2); } int i; for (i = 0; i < N; i++) { tdArr[i] = malloc(N * sizeof(int)); if (tdArr[i] == NULL) { fprintf(stderr, "out of memory\n"); exit(2); } } func(&tdArr); // try to print new array, does not get access violation //assign numbers 0-99 int j; for (i=0; i<N; i++){ for (j=0; j<N; j++){ tdArr[i][j] = i*10+j; } } //print numbers for (i=0; i<N; i++){ for (j=0; j<N; j++){ printf("%d\n", tdArr[i][j]); } } //free internal arrays for (i=0; i<N; i++){ free(tdArr[i]); } //free outer array free(tdArr); return 0; } </code></pre>

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