distinctmatrix.c

/*WAP (write a program) which generate random values from 1 to 16 and put it in a matrix of 4*4.
Obviously each element of this matrix should be distinct.*/
/*this code generate a matrix of n*n with all its elements are distinct*/
/*very interesting program it is used while making the number puzzle game*/

//youtube: https://youtu.be/fjExIt0YIRI

#include<stdio.h>
#include<malloc.h>
#include<time.h>
int main()
{   int n, *mat,row,col;
    int i,j,flag,num;
    srand(time(0));

    printf("Enter value of n for n*n matrix: ");
    scanf("%d",&n);
    mat = calloc(n*n, sizeof(int));
    for(i=0;i<n*n;i++)
        {   num = rand()%(n*n) + 1;
            flag=0;
            /*compare the newly generated number with all the previous elements of matrix*/
            for(j=0;j<i;j++)
                {
                    if(mat[j] == num)
                        {
                            flag++;
                            break;
                        }
                }
            if(flag == 0)//it mean the generated number is unique
                {
                    row = i/n;
                    col = i%n;
                    mat[row * n + col] = num;
                }
                /*if generated number is not unique then run the loop again*/
            else i--;
        }
        /*Now its time to display the dynamically allocated matrix*/
        for(i=0;i<n;i++)
          {
              for(j=0;j<n;j++)
                printf("%2d  ",mat[i*n + j]);
                printf("\n");
        }

    free(mat);

return 0;
}//main