fclose() ends with "Segmentation fault (core dumped)"

I didn't find the answer on internet if there is please link it...

#include <stdio.h>

int main(){
    FILE*fp;
    char arr[4];
    printf("Opening...\n");
    fp=fopen("slide.txt", "r");
    printf("Opened\n");
    if(fp==NULL){
        printf("No such file\n");
        return 1;
    }
    fscanf(fp, "%s", arr);
    printf("Printing...\n");
    printf("%s\n", arr);
    printf("Printed\n");
    printf("Closing...\n");
    fclose(fp);
    printf("Closed\n");
    return 0;
}

Content of the file:

ciao

Output that I have:

Opening...
Opened
Printing...
ciao
Printed
Closing...
Segmentation fault (core dumped)

Declare the character array at least like

char arr[5];

and use

fscanf(fp, "%4s", arr);

That is you need to reserve a space in the array for the terminating zero character '\0' for the read string.