C program for matrix multiplication





#include<stdio.h>
int main(){
  int a[5][5],b[5][5],c[5][5],i,j,k,sum=0,m,n,o,p;
  printf("\nEnter the row and column of first matrix");
  scanf("%d %d",&m,&n);
  printf("\nEnter the row and column of second matrix");
  scanf("%d %d",&o,&p);
  if(n!=o){
      printf("Matrix mutiplication is not possible");
      printf("\nColumn of first matrix must be same as row of second matrix");
  }
  else{
      printf("\nEnter the First matrix->");
      for(i=0;i<m;i++)
      for(j=0;j<n;j++)
           scanf("%d",&a[i][j]);
      printf("\nEnter the Second matrix->");
      for(i=0;i<o;i++)
      for(j=0;j<p;j++)
           scanf("%d",&b[i][j]);
      printf("\nThe First matrix is\n");
      for(i=0;i<m;i++){
      printf("\n");
      for(j=0;j<n;j++){
           printf("%d\t",a[i][j]);
      }
      }
      printf("\nThe Second matrix is\n");
      for(i=0;i<o;i++){
      printf("\n");
      for(j=0;j<p;j++){
           printf("%d\t",b[i][j]);
      }       
      }
      for(i=0;i<m;i++)
      for(j=0;j<p;j++)
           c[i][j]=0;
      for(i=0;i<m;i++){ //row of first matrix
      for(j=0;j<p;j++){  //column of second matrix
           sum=0;
           for(k=0;k<n;k++)
               sum=sum+a[i][k]*b[k][j];
           c[i][j]=sum;
      }
      }
  }
  printf("\nThe multiplication of two matrix is\n");
  for(i=0;i<m;i++){
      printf("\n");
      for(j=0;j<p;j++){
           printf("%d\t",c[i][j]);
      }
  }
  return 0;
}


Algorithm:

Multiplication of two matrixes:

Rule: Multiplication of two matrices is a valid operation only when the first matrix has dimensions m x n and the second matrix has dimensions n x r, where m, n, and r are positive integers.

Multiplication of two matrixes is defined as









Where 1 i  m and 1 ≤ j  n

For example:
Suppose two matrixes A and B of size of 2 x 2 and 2 x 3 respectively:











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