﻿ Example of C Program/Code to Accept a matrix and interchange the main diagonal elements of the matrix
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# Accept a matrix and interchange the main diagonal elements of the matrix

```/* Write a C program to accept a matrix of order M x N and store its elements *
* and interchange the main diagonal elements of the matrix                   *
with that of the secondary diagonal elements                               */```

#include <stdio.h>

void main ()
{

static int ma[10][10];
int i,j,m,n,a;

printf ("Enetr the order of the matix \n");
scanf ("%d %d",&m,&n);

if (m ==n )
{
printf ("Enter the co-efficients of the matrix\n");
for (i=0;i<m;++i)
{
for (j=0;j<n;++j)
{
scanf ("%dx%d",&ma[i][j]);
}
}

printf ("The given matrix is \n");
for (i=0;i<m;++i)
{
for (j=0;j<n;++j)
{
printf (" %d",ma[i][j]);
}
printf ("\n");
}

for (i=0;i<m;++i)
{
a = ma[i][i];
ma[i][i] = ma[i][m-i-1];
ma[i][m-i-1] = a;
}

printf ("THe matrix after changing the \n");
printf ("main diagonal & secondary diagonal\n");
for (i=0;i<m;++i)
{
for (j=0;j<n;++j)
{
printf (" %d",ma[i][j]);
}
printf ("\n");
}
}
else
printf ("The givan order is not square matrix\n");

} /* end of main() */

/*----------------------------------------------------
Output
Enetr the order of the matix
3 3
Enter the co-efficients of the matrix
1 2 3
4 5 6
7 8 9
The given matrix is
1 2 3
4 5 6
7 8 9
THe matrix after changing the
main diagonal & secondary diagonal
3 2 1
4 5 6
9 8 7
----------------------------------------------------------*/