/* Matrix multiplication - Develop a function that takes as arguments 3 matrices a , b , c and 3 integer variables l,m,n. Calculate product of a and b and store the result in c. Also write a main routine which will test whether the input matrices a and b are conformal to multiplication - May 2013 */

#include  <stdio.h>
#include  <conio.h>

void  read(int  x[ ][10], int  nr, int  nc) ;
void  multiply(int  a[ ][10], int  b[ ][10], int  c[ ][10], int  l, int  m, int  n) ;
void  show(int  y[ ][10], int  nr, int  nc) ;


void main()
{
    int  a[10][10], b[10][10], c[10][10], nra, nca, nrb, ncb ;
    clrscr();
    printf("Enter the number of rows and columns of first matrix: ");
    scanf("%d %d", &nra, &nca) ;
    printf("Enter the number of rows and columns of second matrix: ");
    scanf("%d %d", &nrb, &ncb) ;
    if(nca==nrb)
        {
            printf("Enter elements of first matrix row-wise: \n");
            read(a,nra,nca);
            printf("Enter elements of second matrix row-wise: \n");
            read(b,nrb,ncb);
            multiply(a,b,c,nra,nca,ncb);
            printf("Result of matrix multiplication is: \n");
            show(c,nra,ncb);
        }
    else
        printf("Two given Matrices do not conform to multiplication");
    getch();
}

void  read(int  x[ ][10], int  nr, int  nc)
{
    int  r, c ;
    for(r=0 ; r<nr ; r++)
        for(c=0 ; c<nc ; c++)
            scanf("%d", &x[r][c]) ;
}

void  multiply(int  a[ ][10], int  b[ ][10], int  c[ ][10], int  l, int  m, int  n)
{
    int  i, j, k ;
    for(i=0 ; i<l ; i++)
        for(j=0 ; j<n ; j++)
            {
                c[i][j]=0 ;
                for(k=0 ; k<m ; k++)
                    c[i][j]=c[i][j]+a[i][k]*b[k][j] ;
            }
}

void  show(int  y[ ][10], int  nr, int  nc)
{
    int  r, c ;
    for(r=0 ; r<nr ; r++)
        {
            for(c=0 ; c<nc ; c++)
                printf("%d ", y[r][c]) ;
            printf("\n") ;
        }
}

/*
Output1:

Enter the number of rows and columns of first matrix: 2  3
Enter the number of rows and columns of second matrix: 3  2
Enter elements of first matrix:
1 2 4
3 5 6
Enter elements of second matrix:
2 5
1 6
4 3
Result of matrix multiplication is:
20 29
35 63

Output2:

Enter the number of rows and columns of first matrix: 2  3
Enter the number of rows and columns of second matrix: 2  3
Matrices A and B do not conform to multiplication
*/