Increment trigger until you see output upon program crash.

buffer.c

#include <stdio.h>

int main()
{
    int *ip = NULL; //just a convenient way to crash a program :-)
    int i, trigger;

    printf("Trigger at (positive int): ");
    scanf("%d", &trigger);

    for(i = 0; ; i++)  { // essentially an infinite loop
        printf("%d", i%10);
        if (i == trigger)
            *ip = 123; //boom!

    }
    return 0;
}

Observe that low trigger values do not output anything. This is because output is buffered. Only high values such as 10000, output gets written, because buffer size is filled.

Also \n causes buffer to flush.