2D Array in C Write a C program which reads a 4x4 matrices f

2D Array in C

Write a C program which reads a 4x4 matrices from a file and multiplies them.

Function prototype:

Void readMatrices(FILE *fp, int array1[4][4], int array2[4][4]);

Void printMatrices (int array1[4][4], int array2[4][4]);

Void multiply Matrices(int array1[4][4], int array2[4][4], int result[4][4]);

The file will contain the values in the following format:

3 1 2 3 5 6 2 8 7 6 2 8 6 3 6 2 4 6 3 5 7 5 3 6 4 7 8 6 4 3 6 6

0

Solution

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
void readMatrices(FILE *file, int array1[4][4], int array2[4][4])
{
int i,j;
for(i = 0; i < 4; i++)
{
for(j = 0; j < 4; j++)
{
//Use lf format specifier, %c is for character
fscanf(file, \"%d\", &array1[i][j]);

// mat[i][j] -= \'0\';
//printf(\"%d\ \",mat[i][j]); //Use lf format specifier, \ is for new line
}

}

for(i = 0; i < 4; i++)
{
for(j = 0; j < 4; j++)
{
//Use lf format specifier, %c is for character
fscanf(file, \"%d\", &array2[i][j]);

// mat[i][j] -= \'0\';
//printf(\"%d\ \",mat[i][j]); //Use lf format specifier, \ is for new line
}

}

}

void printMatrices (int array1[4][4], int array2[4][4])
{
int i,j;
printf(\"Matrix 1 :\ \");
printf(\"\ \");
for(i = 0; i < 4; i++)
{
for(j = 0; j < 4; j++)
{

printf(\"%d\\t\",array1[i][j]);

  
}
printf(\"\ \");
}

printf(\"Matrix 2 :\ \");
printf(\"\ \");

for(i = 0; i < 4; i++)
{
for(j = 0; j < 4; j++)
{
  
printf(\"%d\\t\",array2[i][j]);

}
printf(\"\ \");

}

}

void multiply_Matrices(int array1[4][4], int array2[4][4], int result[4][4])
{
int i,j,k,sum=0;;
for(i=0;i<4;i++)
{ //row of first matrix
for(j=0;j<4;j++)
{ //column of second matrix
sum=0;
for(k=0;k<4;k++)
sum=sum+array1[i][k]*array2[k][j];
result[i][j]=sum;
}

}
}

int main()
{
int array1[4][4],array2[4][4],result[4][4];

FILE *file;
file=fopen(\"input.txt\", \"r\");

readMatrices(file,array1,array2);
printMatrices(array1,array2);
multiply_Matrices(array1,array2,result);

printf(\"Result is \ \");

int i,j;
for(i = 0; i < 4; i++)
{
for(j = 0; j < 4; j++)
{
  
printf(\"%d\\t\",result[i][j]);

}
printf(\"\ \");

}

fclose(file);
return 0;
}

======================================

Output:

akshay@akshay-Inspiron-3537:~/Chegg$ gcc matrix.c
akshay@akshay-Inspiron-3537:~/Chegg$ ./a.out
Matrix 1 :

3   1   2   3  
5   6   2   8  
7   6   2   8  
6   3   6   2  
Matrix 2 :

4   6   3   5  
7   5   3   6  
4   7   8   6  
4   3   6   6  
Result is
39   46   46   51  
102   98   97   121  
110   110   103   131  
77   99   87   96