C function to transpose matrix does not update matrix - c

Question

I am currently building a matrix calculator (required to make with pointers) as part of my introductory C assignment, and I am currently trying to make an option to Transpose a 3x3 matrix (swapping the rows of a matrix with it's columns).
However, when I apply the function on the matrix nothing happens to it.
Here is the code for the transposition function.
void transposeMatrix(int matrix[3][3]) {
int row;
int col;
int temp = 0;
for (row = 0; row<3; row++) {
for (col = 0; col < 3; col++) {
temp = *(*(matrix+row)+col);
*(*(matrix+row)+col) = *(*(matrix+col)+row);
*(*(matrix+col)+row) = temp;
}
}
}
It is just a standard swapping algorithm with a temp variable.
Here is the code for the printing function
void printMatrix(char *desc,int matrix[3][3]) {
int row;
int column;
printf("matriks %s:\n",desc);
for (row = 0; row < 3; row++) {
for (column = 0; column < 3; column++) {
printf(" %d", matrix[row][column]);
}
printf("\n");
}
}
And here is how I call the function:
int sampleM1[3][3] = {{2,2,4}, {1,1,1}, {1,1,1}};
printMatrix("before transposition", sampleM1);
transposeMatrix(sampleM1);
printMatrix("after transposition" , sampleM1);
The output of the entire operation is that sampleM1 does not change at all. Is there any way to fix this problem?

Answer 1

As #TomKarzes noted above you visit the same index of the matrix twice, and avoid that by starting the inner loop at row + 1. You mentioned that you needed to use pointer syntax, which is fine of course, but swap() now localizes the ugliness (to arguments) for you to change as you see fit.
#include <stdint.h>
#include <stdio.h>
#define N 3
void swap(int *a, int *b) {
int tmp = *a;
*a = *b;
*b = tmp;
}
void printMatrix(int matrix[N][N]) {
for (uint8_t row = 0; row < N; row++)
for (uint8_t col = 0; col < N; col++)
printf("%d%s", matrix[row][col], col + 1 < N ? ", " : "\n");
}
void transposeMatrix(int matrix[N][N]) {
for (uint8_t row = 0; row < N; row++)
for (uint8_t col = row + 1; col < N; col++)
swap(&matrix[row][col], &matrix[col][row]);
}
int main() {
int matrix[N][N] = {
{1, 2, 3},
{4, 5, 6},
{7, 8, 9}
};
printMatrix(matrix);
transposeMatrix(matrix);
printMatrix(matrix);
}
Here is the output of the above:
1, 2, 3
4, 5, 6
7, 8, 9
1, 4, 7
2, 5, 8
3, 6, 9