signed unsigned

//-std=c99 -Wall -Wextra -Wpedantic -Wshadow

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

#include <inttypes.h>

void printBinaryLE(void *v, uint32_t s)
{

    if(!v||s<1)
    {
        printf("error !\n");
        return;
    }

    uint8_t *pv = (uint8_t*) v;
    uint32_t i;

    while(s--)
    {
        i=8;
        while(i--)
        {
            printf("%d", pv[s] >> i & 1u ? 1 : 0);
        }
    }

    printf("\n");
}

int main()
{

    int8_t a = -1;
    uint8_t b = 0xFF;
    int32_t result;

    printf("a DEC: %d HEX: 0x%X BIN (little endian): ", a, a);
    printBinaryLE(&a, sizeof(a));

    printf("%" PRIx8, a);
    printf("\n");

    printf("0x%X\n", a & 0xFF);

    printf("b DEC: %d HEX: 0x%X BIN (little endian): ", b, b);
    printBinaryLE(&b, sizeof(b));

    result = a + b;

    printf("%d + %d = %d\n", a, b, result);

    result = b + b;

    printf("%d + %d = %d\n", b, b, result);

    return 0;
}

/*
output:

a DEC: -1 HEX: 0xFFFFFFFF BIN (little endian): 11111111
ffffffff
0xFF
b DEC: 255 HEX: 0xFF BIN (little endian): 11111111
-1 + 255 = 254
255 + 255 = 510

*/