Identify Trap in Signed vs Unsigned Comparison

Code

#include <stdio.h>
#include <stdint.h>

int safe_compare(int8_t a, uint8_t b)
{
    if (a < 0)
        return 1;

    return ((int)a < (int)b) ? 1 : 0;
}

int main()
{
    int8_t a;
    uint8_t b;

    scanf("%hhd %hhu", &a, &b);
    printf("%d", safe_compare(a, b));
    return 0;
}

Solving Approach