Identify Trap in Signed vs Unsigned Comparison

Code

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

int safe_compare(int8_t a, uint8_t b) {
    uint8_t U_a = a;
    return ((a < 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