8.8.4-PointersOnC-20220215

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int Is_Identity_Matrix(int **arr,int num);
int main(){
	int row=0,ch=0,**matrix=NULL;
	srand((unsigned int)time(0));
	for(fputs("Input the row of matrix:->",stdout);(ch=scanf_s("%d",&row))!=1||row>30;fputs("Input the row of matrix:->",stdout))
		while((ch=getchar())!=EOF&&ch!=10);
	matrix=(int **)calloc(row,sizeof(int *));
	for(int i=0;i<row;matrix[i]=(int *)calloc(row,sizeof(int)),i++);
	for(int i=0;i<row;matrix[i][i]=1,i++);// Build a cell matrix 
	matrix[rand()%row][rand()%row]=1;// Change a random position to 1
	for(int i=0;i<row;i++){
		for(int j=0;j<row;j++)
			printf("%d ",matrix[i][j]);
		fputc(10,stdout);
	}
	printf("The matrix with %d rows %s IdentityMatrix.\n",row,Is_Identity_Matrix(matrix,row)?"is":"isn't");
	for(int i=0;i<row;free(matrix[i]),matrix[i]=NULL,i++);
	free(matrix);
	matrix=NULL;

}
//
int Is_Identity_Matrix(int **arr,int num){
	for(int i=0;i<num;i++)
		for(int j=0;j<num;j++)
			if(arr[i][j]!=(i==j))
				return 0;
return 1;}
/*
1 0 0 0 0 0 0 0 0 0
0 1 0 0 0 0 0 0 0 0
0 0 1 0 0 0 0 0 0 0
0 0 0 1 0 0 0 0 0 0
0 0 0 0 1 0 0 0 0 0
0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 1 0 0 0
0 0 0 0 0 0 0 1 0 0
0 0 0 0 0 0 0 0 1 0
0 0 0 0 0 0 0 0 0 1
*/