/* Addition , Subtraction and Multiplication of Matrices */
#include<stdio.h>
main()
{
    int a[20][20], b[20][20], i,j,m,n,p,q;
    clrscr();
    /*Getting the element of the Matrix1 */
    printf("Enter the order of first matrix\n");
    scanf("%d %d", &m, &n);
    printf("%d %d", m,n);
    printf("\n Enter the element of first matrix\n");
    for(i=0; i<m; i++)
        for(j=0; j<n; j++)
        {
            scanf("%d", &a[i][j]);
        }

    /*Getting the element of the Matrix2 */
    printf("\n Enter the order of second matrix\n");
    scanf("%d %d ", &p,&q);
    printf("%d %d\n", p,q);
    printf("\n Enter the element of second matrix\n");
    for(i=0; i<p; i++)
        for(j=0; j<q; j++)
        {
            scanf("%d", &b[i][j]);
        }
        printf("\n");
    /* Displaying Matrix1 and Matrix2 */
    clrscr();
    printf("\n\t\t Addition, Subtraction, Multiplication of Matrixes\n\n");
    printf("First matrix:\n");
    for(i=0; i<m; i++)
    {
        for(j=0; j<n; j++)
           printf("\t%d", a[i][j]);
        printf("\n");

    }
    printf("\n");
    printf("Second Matrix: \n");
    for(i=0; i<p; i++)
    {
        for(j=0; j<q; j++)
            printf("\t%d", b[i][j]);
        printf("\n");
    }

    if(m==p & n==q) /*Checks whether the orders of the Matrixes are equal */
    {
        add(a,b,m,n);      /*If equal sends to the functions add & mul */
        mul(a,b,m,n,q);
    }
    else
    {
       if(n==p)      /* If columns(Mat.1) = Rows (Mat.2) it Multiplication only possible */
       {
            printf("\n Addition and Subtraction not possible with this order");
            mul(a,b,n,q);
       }
       else
       {
            printf("\n The order of the matrix are not proper");
       }
    }
getch();
}

mul(int m1[20][20], int m2[20][20], int r1, int c1, int c2)

{
    int i,j,k,p[20][20];
    for(i=0; i<r1; i++)
        for(j=0; j<c2; j++)
        {
            p[i][j] =0;
            for(k=0; k<c1; k++)
                p[i][j] += m1[i][k]*m2[k][i];
        }

    printf("\n\t The product: \n");
    for(i=0; i<r1; i++)
    {
        for(j=0; j<c2; j++)
        {
            printf("\t\t %d", p[i][j]);
        }
        printf("\n\n");
    }
}

add(int m1[20][20],int m2[20][20],int r,int c)
{
       int i,j,sum[20][20],diff[20][20];
       for(i=0;i<r;i++)
       for(j=0;j<c;j++)
       {
            sum[i][j]=m1[i][j]+m2[i][j];
            diff[i][j]=m1[i][j]-m2[i][j];
       }
       printf("\n");
       printf("\t The sum:\n");
       for(i=0; i<r; i++)
       {
            for(j=0;j<c;j++)
            printf("\t%d\t",sum[i][j]);
            printf("\n\n");
       }

    printf("\t The difference:\n");
    for(i=0; i<r; i++)
    {
        for(j=0; j<c; j++)
        printf("\t%d\t", diff[i][j]);
        printf("\n\n");
    }

}