MATRIX ADDITION AND MULTIPLICATION

/* Write a C program that uses functions to perform the following:
i) Addition of Two Matrices
ii) Multiplication of Two Matrices
*/

#include<stdio.h>

void main()
{
int ch,i,j,m,n,p,q,k,r1,c1,a[10][10],b[10][10],c[10][10];

printf("************************************");
printf("\n\t\tMENU");
printf("\n**********************************");
printf("\n[1]ADDITION OF TWO MATRICES");
printf("\n[2]MULTIPLICATION OF TWO MATRICES");
printf("\n[0]EXIT");
printf("\n**********************************");
printf("\n\tEnter your choice:\n");
scanf("%d",&ch);

switch(ch)
{
default:
printf("Invalide choice\n");
exit(1);

case 1:
printf("Input rows and columns of A & B Matrix:");
scanf("%d%d",&r1,&c1);
printf("Enter elements of matrix A:\n");
read_matrix(a,r1,c1);
printf("Enter elements of matrix B:\n");
read_matrix(b,r1,c1);
printf("\n =====Matrix Addition=====\n");
for(i=0;i<r1;i++)
{
for(j=0;j<c1;j++)
{
c[i][j]= a[i][j]+b[i][j];
}
printf("\n");
}
write_matrix(c,r1,c1);
break;

case 2:
printf("Input rows and columns of A matrix:");
scanf("%d%d",&m,&n);
printf("Input rows and columns of B matrix:");
scanf("%d%d",&p,&q);
if(n==p)
{
printf("resultant matrix is %d*%d\n",m,q);
printf("Input A matrix\n");
read_matrix(a,m,n);
printf("Input B matrix\n");
/*Function call to read the matrix*/
read_matrix(b,p,q);
/*Function for Multiplication of two matrices*/
printf("\n =====Matrix Multiplication=====\n");
for(i=0;i<m;++i)
for(j=0;j<q;++j)
{
c[i][j]=0;
for(k=0;k<n;++k)
c[i][j]=c[i][j]+a[i][k]*b[k][j];
}

printf("Resultant of two matrices:\n");
write_matrix(c,m,q);
}
/*end if*/
else
{
printf("Matrices cannot be multiplied.");
}
/*end else*/
break;

case 0:
printf("\n Choice Terminated");
exit();
break;

}

}

/*Function read matrix*/
int read_matrix(int a[10][10],int m,int n)
{
int i,j;
for(i=0;i<m;i++)
for(j=0;j<n;j++)
scanf("%d",&a[i][j]);
return 0;
}

/*Function to write the matrix*/
int write_matrix(int a[10][10],int m,int n)
{
int i,j;
for(i=0;i<m;i++)
{
for(j=0;j<n;j++)
printf("%5d",a[i][j]);
printf("\n");
}
return 0;
}