Example: Matrix Rotation 90 Degrees Clockwise in C using Function

// Matrix Rotation 90 Degrees Clockwise in C using Function
#include <stdio.h>
#define N 4

void rotate90DegClockwise(int x[N][N]);
void printMatrix(int x[N][N]);

// It's the driver function
int main() {
    int arru[N][N] = {
    	{1, 2, 3, 4},
    	{5, 6, 7, 8},
    	{9, 10, 11, 12},
    	{13, 14, 15, 16}
    };

    printf("-----The input matrix before 90 degrees clock-wise rotation-----\n\n");
    printMatrix(arru);

    // this function will be rotate each element clock-wise
    rotate90DegClockwise(arru);

    printf("\n-----The matrix after 90 degrees clock-wise rotation-----\n\n");
    printMatrix(arru);
    return 0;
}

// This function will rotate the matrix 90 degree clock-wise
void rotate90DegClockwise(int a[N][N]) {

    // It will traverse the each cycle
    for (int i = 0; i < N / 2; i++) {
        for (int j = i; j < N - i - 1; j++) {
 
            // It will swap elements of each cycle in clock-wise direction
            int temp = a[i][j];
            a[i][j] = a[N - 1 - j][i];
            a[N - 1 - j][i] = a[N - 1 - i][N - 1 - j];
            a[N - 1 - i][N - 1 - j] = a[j][N - 1 - i];
            a[j][N - 1 - i] = temp;
        }
    }
}

// This function will print the transformed matrix
void printMatrix(int arr[N][N]) {
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++)
            printf("%d\t", arr[i][j]);
        printf("\n\n");
    }
}