Rotate a NxN 2D matrix by 90 degrees – C Program Source Code

The below program does the following:

1. Creates a 2D matrix whose size can be input through Command Line arguments.
2. Prints the 2D Matrix.
3. Rotates the matrix by right angle (90 degrees) clockwise.

Source Code:

#include<stdio.h>
#include<stdlib.h>
#define DEFN 6

int** CreateMatrix(int**, int N);
void PrintMatrix(int**, int N);
int** RotateMatrix(int**,int N);

int main(int argc, char *argv[])
{

 int **matrix = NULL;
 int N;
 if(argc==2)
 N = atoi(argv[1]);
 else
 N = DEFN;
 matrix = CreateMatrix(matrix, N);
 printf("\nInitialMatrix:\n");
 PrintMatrix(matrix,N);
 printf("\n");
 matrix = RotateMatrix(matrix,N);
 printf("\nRotated Matrix:\n");
 PrintMatrix(matrix,N);

 char c = getchar();

 return(0);
}
int** CreateMatrix(int **matrix, int N)
{
 int i,j;
 matrix = (int**) calloc(N,sizeof(int*));
 for(i=0; i<N; i++)
 {
 *(matrix+i) = (int*) calloc(N, sizeof(int));
 for(j=0; j<N; j++)
 *(*(matrix+i)+j) = rand();
 }
 return(matrix);
}
void PrintMatrix(int **matrix, int N)
{
 int i,j;
 for(i=0; i<N; i++)
 {
 for(j=0; j<N; j++)
 printf("%6d ", *(*(matrix+i)+j));
 printf("\n");
 }
} 

int** RotateMatrix(int **matrix, int N)
{
 int i,temp,layer;

 for(layer=0; layer<(N/2); layer++)
 for(i=layer; i<N-layer-1; i++)
 {

 temp = *(*(matrix+N-i-1)+layer);
 *(*(matrix+N-i-1)+layer) = *(*(matrix+N-layer-1)+N-i-1);
 *(*(matrix+N-layer-1)+N-i-1) = *(*(matrix+i)+N-layer-1);
 *(*(matrix+i)+N-layer-1) = *(*(matrix+layer)+i);
 *(*(matrix+layer)+i) = temp;
 }
 return(matrix);
}

OUTPUT:

InitialMatrix:
 41 18467 6334 26500 19169 15724
11478 29358 26962 24464 5705 28145
23281 16827 9961 491 2995 11942
4827 5436 32391 14604 3902 153
292 12382 17421 18716 19718 19895
5447 21726 14771 11538 1869 19912
Rotated Matrix:
 5447 292 4827 23281 11478 41
21726 12382 5436 16827 29358 18467
14771 17421 32391 9961 26962 6334
11538 18716 14604 491 24464 26500
1869 19718 3902 2995 5705 19169
19912 19895 153 11942 28145 15724