matrixMult.c

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

//Global vars
int matrix1[25][25], matrix2[25][25], result[25][25];
int r1, c1, r2, c2, i, j, k; //throughout the program i and j are variables reserved for use in for loops

int initSetup()
{
	printf("Enter the no. of rows in the first matrix and press the return key then proceed to enter the no. of coloumns \n");
	scanf("%d", &r1);
	printf("x\n");
	scanf("%d", &c1);

	printf("Enter the no. of rows in the second matrix and press the return key then proceed to enter the no. of coloumns \n");
	scanf("%d", &r2);
	printf("x\n");
	scanf("%d", &c2);
}

int handleErr()
{
	printf("Error! the matrices cannot be multiplied\n\nEnter new values\n");
	initSetup();
}

int checkForErr()
{
	if (c1 != r2)
	{
		return true;
	}
}

getValues()
{
	printf("\nEnter elements a[i][j] of the first matrix(%dx%d)\n", r1, c1);
	for(i = 1; i <= r1; i++)
	{
		for(j = 1; j <= c1; j++)
		{
			// taking a[i][j] as general element of Ist matrix
			printf("Element a[%d][%d]= ", i, j);
			scanf("%d",&matrix1[i][j]);
		}
	}

	printf("\nEnter elements b[i][j] of the second matrix(%dx%d)\n", r2, c2);
	for(i = 1; i <= r2; i++)
	{
		for(j = 1; j <= c2; j++)
		{
			// taking b[i][j] as general element of IInd matrix
			printf("Element b[%d][%d]= ", i, j);
			scanf("%d",&matrix2[i][j]);
		}
	}
}

multiplyMatrices()
{
    int sum=0;
    for(i=1;i<=r1;i++){
        for(j=1;j<=c2;j++){
            for(k=1;k<=r2;k++){
                sum+=matrix1[i][k]*matrix2[k][j];
            }
            result[i][j]=sum;
            sum=0;
        }
    }
}

printResult()
{
	for(i = 1; i <= c1; i++)
	{
		for(j = 1; j <= c2; j++)
		{
			printf("%d\t", result[i][j]);
		}
		printf("\n");
	}
}

int main()
{
	initSetup();

	if (checkForErr() == true)
	{
		handleErr();
	};

	getValues();

	multiplyMatrices();

	printResult();

	return 0;
}