Matrix Calculator

/*
 * Simple Matrix Calculator
 * by: Rifai M. Hanif
 */

#include <stdio.h>
#include <stdlib.h>

typedef enum {false, true} bool;

int** initMatrix(char* name, int rows, int cols, bool input) {
    int** matrix;
    char buffer[80];
    matrix = (int**) malloc(rows * sizeof(int*));

    for (int i = 0; i < rows; i++) {
        matrix[i] = (int*) malloc(cols * sizeof(int));

        if (input)
        {
            for (int j = 0; j < cols; j++)
            {
                printf("%s(%d,%d): ", name, i+1, j+1);
                fgets(buffer, sizeof(buffer), stdin);
                sscanf(buffer, "%d", &matrix[i][j]);
            }
        }
    }

    return matrix;
}

void printMatrix(char* title, int** matrix, int rows, int cols)
{
    printf("\n%s(%dx%d)\n", title, rows, cols);
    for (int i = 0; i < rows; i++)
    {
        for (int j = 0; j < cols; j++)
        {
            printf("%d\t", matrix[i][j]);
        }
        printf("\n");
    }
}

int** multiplyMatrix(int** m1, int r1, int c1, int** m2, int r2, int c2)
{
    if (c1 != r2)
    {
        printf("The number of columns in first matrix should be equal to the number of rows in the second.\n");
        return false;
    }

    int** matrix = initMatrix("M", r1, c2, false);

    for (int i = 0; i < r1; i++)
    {
        for (int j = 0; j < c2; j++)
        {
            matrix[i][j] = 0;
            for (int k = 0; k < c1; k++)
            {
                matrix[i][j] += m1[i][k] * m2[k][j];
            }
        }
    }

    return matrix;
}

int** addOrSubstractMatrix(int** m1, int r1, int c1, int** m2, int r2, int c2, char op)
{
    if (r1 != r2 || c1 != c2)
    {
        printf("Size not match.\n");
        return false;
    }

    if(op != '+' && op != '-')
    {
        printf("%c Invalid operation.\n", op);
        return false;
    }

    int** matrix = initMatrix("M", r1, c1, false);

    for (int i = 0; i < r1; i++)
    {
        for (int j = 0; j < c1; j++)
        {
            if (op == '+')
                matrix[i][j] = m1[i][j] + m2[i][j];
            else
                matrix[i][j] = m1[i][j] - m2[i][j];
        }
    }

    return matrix;
}

int** multiplyMatrixBy(int** m, int r, int c, int n)
{
    int** matrix = initMatrix("M", r, c, false);

    for (int i = 0; i < r; i++)
    {
        for (int j = 0; j < c; j++)
        {
            matrix[i][j] = m[i][j] * n;
        }
    }

    return matrix;
}

int** powerMatrix(int** m, int r, int c, int n)
{
    if (r != c)
    {
        printf("The number of columns should be equal to the number of rows.\n");
        return false;
    }

    int** matrix = m;

    for (int i = 1; i < n; i++)
    {
        matrix = multiplyMatrix(matrix, r, c, m, r, c);
    }

    return matrix;
}

void clean()
{
    #if defined(WIN32) && !defined(UNIX)
        system("cls");
    #else
        system("clear");
    #endif

    printf("=================================================\n");
    printf("*               MATRIX CALCULATOR               *\n");
    printf("*              by: Rifa'i M. Hanif              *\n");
    printf("=================================================\n\n");
}

void pause()
{
    printf("\nPress enter to continue...");
    getchar();
}

int main()
{
    clean();

    int rA, rB, cA, cB, op, n;
    char buffer[80];

    printf("Matrix A\n");
    printf("========\n");
    printf("Rows\t: ");
    fgets(buffer, sizeof(buffer), stdin);
    sscanf(buffer, "%d", &rA);
    printf("Columns\t: ");
    fgets(buffer, sizeof(buffer), stdin);
    sscanf(buffer, "%d", &cA);
    int** A = initMatrix("A", rA, cA, true);

    printf("\nMatrix B\n");
    printf("Rows\t: ");
    fgets(buffer, sizeof(buffer), stdin);
    sscanf(buffer, "%d", &rB);
    printf("Columns\t: ");
    fgets(buffer, sizeof(buffer), stdin);
    sscanf(buffer, "%d", &cB);
    int** B = initMatrix("B", rB, cB, true);

    int** C = initMatrix("C", rA, cB, false);
    int** D = initMatrix("D", rB, cA, false);
    int** E = initMatrix("E", rA, cA, false);
    int** F = initMatrix("E", rB, cB, false);

    while(true) {
        clean();

        printMatrix("Matrix A", A, rA, cA);
        printMatrix("Matrix B", B, rB, cB);

        printf("\n\nOptions:\n");
        printf("========\n");
        printf("1 - A*B\n");
        printf("2 - B*A\n");
        printf("3 - A+B\n");
        printf("4 - A-B\n");
        printf("5 - B-A\n");
        printf("6 - Multiply A by n\n");
        printf("7 - Multiply B by n\n");
        printf("8 - Raise A to the power of n\n");
        printf("9 - Raise B to the power of n\n");
        printf("10 - Restart\n");
        printf("11 - Exit\n\n");
        printf("Your choice: ");
        fgets(buffer, sizeof(buffer), stdin);
        sscanf(buffer, "%d", &op);

        switch(op) {
            case 1:
                C = multiplyMatrix(A, rA, cA, B, rB, cB);
                if (C)
                    printMatrix("A*B", C, rA, cB);
                pause();
                break;
            case 2:
                D = multiplyMatrix(B, rB, cB, A, rA, cA);
                if (D)
                    printMatrix("B*A", D, rB, cA);
                pause();
                break;
            case 3:
                E = addOrSubstractMatrix(A, rA, cA, B, rB, cB, '+');
                if (E)
                    printMatrix("A+B", E, rA, cA);
                pause();
                break;
            case 4:
                E = addOrSubstractMatrix(A, rA, cA, B, rB, cB, '-');
                if (E)
                    printMatrix("A-B", E, rA, cA);
                pause();
                break;
            case 5:
                E = addOrSubstractMatrix(B, rB, cB, A, rA, cA, '-');
                if (E)
                    printMatrix("B-A", E, rA, cA);
                pause();
                break;
            case 6:
                printf("n = ");
                fgets(buffer, sizeof(buffer), stdin);
                sscanf(buffer, "%d", &n);
                E = multiplyMatrixBy(A, rA, cA, n);
                if (E)
                    printMatrix("nA", E, rA, cA);
                pause();
                break;
            case 7:
                printf("n = ");
                fgets(buffer, sizeof(buffer), stdin);
                sscanf(buffer, "%d", &n);
                F = multiplyMatrixBy(B, rB, cB, n);
                if (F)
                    printMatrix("nB", F, rB, cB);
                pause();
                break;
            case 8:
                printf("n = ");
                fgets(buffer, sizeof(buffer), stdin);
                sscanf(buffer, "%d", &n);
                E = powerMatrix(A, rA, cA, n);
                if (E)
                    printMatrix("A power n", E, rA, cA);
                pause();
                break;
            case 9:
                printf("n = ");
                fgets(buffer, sizeof(buffer), stdin);
                sscanf(buffer, "%d", &n);
                F = powerMatrix(B, rB, cB, n);
                if (F)
                    printMatrix("B power n", F, rB, cB);
                pause();
                break;
            case 10:
                return main();
                break;
            default:
                clean();
                printf("\nSee you next time...");
                exit(0);
                break;
        }
    }

    return 0;
}