#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <limits.h>

int main()
{
    int a[20][20],m,n,i,j,lin,col,x;
    FILE *f;
    printf("m=");
    scanf("%d",&m);
    printf("n=");
    scanf("%d",&n);
    srand(time(NULL));
    for(i=0;i<n;i++){
        for(j=0;j<n;j++){
            a[i][j]=10+rand()%90;
            printf("%d ",a[i][j]);
        }
        printf("\n");
    }
    f=fopen("metrice.bin","wb+");
    fwrite(a,sizeof(int),20*20,f);
    printf("Pozitia elementului pe care il modific: ");
    scanf("%d,%d",&lin,&col);
    fseek(f,(lin*20+col)*sizeof(int),SEEK_SET);
    fread(&x,sizeof(int),1,f);
    x=10*x;
    fseek(f,-sizeof(int),SEEK_CUR);
    fwrite(&x,sizeof(int),1,f);
    rewind(f);
    fread(a,sizeof(int),400,f);
    for(i=0;i<m;i++){
        for(j=0;j<m;j++) printf("%d ",a[i][j]);
        printf("\n");
    }
    fclose(f);
    return 0;
}