Display Prime Numbers Between two Intervals

#include <stdio.h>

int main()
{
    int n1, n2, i, j, flag;
    printf("Enter two numbers(interval) : ");
    scanf("%d %d", &n1, &n2);

    printf("Prime numbers between %d and %d are: ", n1, n2);
    for (i = n1 + 1; i < n2; ++i)
    {
        flag = 0;
        for (j = 2; j <= i / 2; ++j)
        {
            if (i % j == 0)
            {
                flag = 1;
                break;
            }
        }
        if (flag == 0)
            printf("%d ", i);
    }

    return 0;
}

OUTPUT

Enter two numbers(interval) : 10 100
Prime numbers between 10 and 100 are: 11 13 17 19 23 29 31 37 41 43 47 53 59 61
67 71 73 79 83 89 97