Cannot modify a matrix element's value with a function - c

Question

i'm trying to create a function that sets to 0 the value of every matrix element a[i][j] which is divisible by both i and j. I tried to do it this way but the program just "exits" without giving any error or warning after the matrix=editMat(matrix, nrows, ncols); line.
#include <stdio.h>
#include <stdlib.h>
FILE *openFileR(const char *);
int rows(FILE *);
int cols(FILE *);
int **readMat(FILE *, int **);
int **allocMat(int, int);
void printMat(int **, int, int);
int **editMat(int, int, int**);
int main()
{
FILE *fp, *fpout;
fp=openFileR("matrixmag.txt");
int nrows=rows(fp); int ncols=cols(fp);
int **matrix=allocMat(nrows, ncols);
readMat(fp, matrix);
printMat(matrix, nrows, ncols);
matrix=editMat(nrows, ncols, matrix);
printMat(matrix, nrows, ncols);
return 0;
}
int **editMat(int nrows, int ncols, int **matrix )
{
int i, j;
for(i=0; i<nrows; i++)
{
for(j=0; j<ncols; j++)
{
if((matrix[i][j])%i==0 && (matrix[i][j])%j==0)
{
matrix[i][j]=0;
}
}
}
return matrix;
}
int **readMat(FILE *fp, int **matrix)
{
int value, row, col;
while(fscanf(fp, "%d %d %d", &value, &row, &col)!=EOF)
{
matrix[row][col]=value;
}
return matrix;
}
int **allocMat(int nrows, int ncols)
{
int **matrix=malloc(nrows*(sizeof(int *)));
for(int i=0; i<nrows; i++)
{
matrix[i]=malloc(ncols*sizeof(int));
}
return matrix;
}
void printMat(int **matrix, int nrows, int ncols)
{
for(int i=0; i<nrows; i++)
{
for(int j=0; j<ncols; j++)
{
printf("%d ", matrix[i][j]);
}
printf("\n");
}
}
int cols(FILE *fp)
{
int columns;
fscanf(fp, "%d", &columns);
printf("Columns:%d\n", columns);
return columns;
}
int rows(FILE *fp)
{
int lines;
fscanf(fp,"%d", &lines);
printf("Rows:%d\n", lines);
return lines;
}
FILE *openFileR(const char *nome_file)
{
FILE *fp;
printf("File name: %s\n", nome_file);
fp=fopen(nome_file, "r");
if(fp==NULL)
{
printf("Couldn't open file\n");
exit(-1);
}
else
printf("File correctly opened\n");
return fp;
}
Input file is
3 3
2 0 0
7 0 1
6 0 2
9 1 0
5 1 1
1 1 2
4 2 0
3 2 1
8 2 2
sorry about the errors, i didn't check what i wrote before

Answer 1

Just figured out i was trying to divide a number by 0, since i and j were both initialized to 0
int **editMat(int nrows, int ncols, int **matrix )
{
int i, j;
for(i=0; i<nrows; i++)
{
for(j=0; j<ncols; j++)
{
if((matrix[i][j])%i==0 && (matrix[i][j])%j==0)
{
matrix[i][j]=0;
}
}
}
return matrix;
}
This way it works fine
int **editMat(int nrows, int ncols, int **matrix )
{
int i, j;
for(i=1; i<nrows; i++)
{
for(j=1; j<ncols; j++)
{
if((matrix[i][j])%i==0 && (matrix[i][j])%j==0)
{
matrix[i][j]=0;
}
}
}
return matrix;
}
Thanks everybody for the help anyway :)