main()
{
int mat1[3][3] = {1,2,3,4,5,6,7,8,9};
int mat2[3][3] = {1,2,3,4,5,6,7,8,9};
int res[3][3];
int i,j,k;
for (i=0; i<3; i++)
for (j=0; j<3; j++)
res[i][j] = 0;
for (i=0; i<3; i++)
for (j=0; j<3; j++)
for (k=0; k<3; k++)
*(*(res + i) + j) += (*(*(mat1 + i) + k)) * (*(*(mat2 + k) 
+ j));

for (i=0; i<3; i++)
{
for (j=0; j<3; j++)
printf ("%d\t", res[i][j]);
printf ("\n");
}
printf("\n");
}

9

#include<stdio.h> 
#include<conio.h> 
int main() 
{ 
    int mul(int,int); 
    int n1,n2,f=1,ans; 
    while(f==1) 
    { 
        printf("\n***MULTIPLICATION OF TWO NATURAL 
NUMBERS***"); 
        printf("\nEnter Two Numbers: "); 
        scanf("%d %d",&n1,&n2); 
        if(n1<=0||n2<=0) 
        { 
            printf("\nInvalid Choice..."); 
            printf("\nDo You Want To Try 
Again...\n1.Yes\n2.No"); 
            scanf("%d",&f); 
        } 
        else 
        { 
            printf("\nAns = %d",mul(n1,n2),"\n"); 
            printf("\nDo You Want To 
Continue:\n1.Yes\n2.No\n"); 
            scanf("%d",&f); 
        } 
    } 
} 
int mul(int a,int b) 
{ 
    return((b-1)*a+a); 
}

#include<stdio.h>
#include<conio.h>
int main()
{
    int n,m,i,j,k;
    int a[38][38],b[38][38],p[38][38];
    printf("\nEnter the number of rows and coloumns ");
    scanf("%d %d",&n,&m);
    printf("\nEnter the elements of first matrix ");
    for(i=0;i<n;i++)
    {
                    for(j=0;j<m;j++)
                    {
                                    scanf("%d",(*(a+i)+j));
                    }
    }
    printf("\nMatrix is ");
     for(i=0;i<n;i++)
    {
                     printf("\n");
                    for(j=0;j<m;j++)
                    {
                                    printf("%d",*(*(a+i)+j));
                                    printf("\t");
                    }
    }
     printf("\nEnter the elements of second matrix ");
    for(i=0;i<n;i++)
    {
                    for(j=0;j<m;j++)
                    {
                                    scanf("%d",(*(b+i)+j));
                    }
    }
    printf("\nMatrix is ");
     for(i=0;i<n;i++)
    {
                     printf("\n");
                    for(j=0;j<m;j++)
                    {
                                    printf("%d",*(*(b+i)+j));
                                    printf("\t");
                    }
    }
    printf("\nAfter multiplication ");
    for(i=0;i<n;i++)
    {
                    for(j=0;j<m;j++)
                    {
                    p[i][j]=0;
                    for(k=0;k<n;k++)
                    {
                    p[i][j]+=a[i][k]*b[k][j];
                    }
                    }
                    }
                    for(i=0;i<n;i++)
                    {
                    printf("\n");
                    for(j=0;j<m;j++)
                    {
                    printf("%d",*(*(p+i)+j));
                    printf("\t");
                    }
                    }
                                                           
                        
    getch();
}

// write a program to multipication of a matrix
#include<stdio.h>
#include<conio.h>
#include<alloc.h>
void main()
{
int *ptr1,*ptr2,*ptr3;
int m,n,i,j,k;
printf("enter m & n=");
scanf("%d%d",&m,&n);
ptr1=(int*)malloc((m*n)*sizeof(int));
ptr2=(int*)malloc((m*n)*sizeof(int));
ptr3=(int*)malloc((m*n)*sizeof(int));
printf("enter elements of 1st matrix=");
for(i=0;i<n;i++)
{
for(j=0;j<n;j++)
{
scanf("%d",((ptr1+i)+j)) ;
}
}
printf("enter elements of 2nd matrix=");
for(i=0;i<n;i++)
{
for(j=0;j<n;j++)
{
scanf("%d",((ptr2+i)+j)) ;
}
}
for(i=0;i<n;i++)
{
for(j=0;j<n;j++)
{
*((ptr3+i)+j)=0;
for(k=0;k<n;k++)
{
*((ptr3+i)+j)=*((ptr3+i)+j)+(*((ptr1+i)+j))*(*((ptr2+j)+k));
}
}
}
printf("multipication is=\n");
for(i=0;i<n;i++)
{
for(j=0;j<n;j++)
{
printf("%d\t",*((ptr3+i)+j)) ;
}
printf("\n");
}
getch();
}