C Exercises: Check whether a given matrix is an identity matrix
C Array: Exercise-31 with Solution
Write a program in C to check whether a given matrix is an identity matrix.
Visual Presentation:

Sample Solution:
C Code:
#include <stdio.h>
// In a square matrix, if all the main diagonal elements are 1's and
// all the remaining elements are 0's, it is called an Identity Matrix.
int main() {
int arr1[10][10];
int r1, c1;
int i, j, yn = 1;
// Display the purpose of the program
printf("\n\n Check whether a given matrix is an identity matrix :\n");
printf("-----------------------------------------------------------\n");
// Input the number of Rows for the matrix
printf("Input number of Rows for the matrix :");
scanf("%d", &r1);
// Input the number of Columns for the matrix
printf("Input number of Columns for the matrix :");
scanf("%d", &c1);
// Input elements into the matrix
printf("Input elements in the matrix :\n");
for(i = 0; i < r1; i++) {
for(j = 0; j < c1; j++) {
printf("element - [%d],[%d] : ", i, j);
scanf("%d", &arr1[i][j]);
}
}
// Display the matrix
printf("The matrix is :\n");
for(i = 0; i < r1; i++) {
for(j = 0; j < c1 ;j++) {
printf("% 4d", arr1[i][j]);
}
printf("\n");
}
// Check whether the matrix is an identity matrix or not
for(i = 0; i < r1; i++) {
for(j = 0; j < c1; j++) {
if (arr1[i][j] != 1 && arr1[j][i] != 0) {
yn = 0;
break;
}
}
}
// Display the result
if(yn == 1) {
printf(" The matrix is an identity matrix.\n\n");
} else {
printf(" The matrix is not an identity matrix.\n\n");
}
return 0;
}
Sample Output:
Check whether a given matrix is an identity matrix : ----------------------------------------------------------- Input number of Rows for the matrix :3 Input number of Columns for the matrix :3 Input elements in the first matrix : element - [0],[0] : 1 element - [0],[1] : 0 element - [0],[2] : 0 element - [1],[0] : 0 element - [1],[1] : 1 element - [1],[2] : 0 element - [2],[0] : 0 element - [2],[1] : 0 element - [2],[2] : 1 The matrix is : 1 0 0 0 1 0 0 0 1 The matrix is an identity matrix.
Flowchart :

C Programming Code Editor:
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