Float analyser

main.c

#include <stdio.h>
#include <unistd.h>
#include <strings.h>

void my_put_char(char c)
{
    write(1, &c, 1);
}

void my_put_nbr_base(int nb, const char *base)
{
    size_t base_value = strlen(base);
    if (nb < 0) {
        my_put_char('-');
        nb *= -1;
    }
    if (nb >= base_value) {
        my_put_nbr_base(nb / base_value, base);
    }
    my_put_char(base[nb % base_value]);
}

int main(int argc, char const *argv[])
{
    setvbuf(stdout, NULL, _IONBF, 0);

    float nb = -65.50009;
    unsigned int hexNb = *(int *)&nb;

    float sign = hexNb >> 31 ? -1 : 1;
    // Si 1 alors négatif;

    printf("Sign = ");
    my_put_nbr_base(sign, "01");
    printf(", (%c)\n", sign < 0 ? '-' : '+');

    unsigned int exponent = ((hexNb & 0x7f800000) >> 23) - 127;

    printf("Exponent = ");
    my_put_nbr_base((hexNb & 0x7f800000) >> 23, "01");
    printf(", (%d)\n", exponent);

    unsigned int mantisse = hexNb & 0x7FFFFF;

    printf("Mantisse = ");
    my_put_nbr_base(mantisse, "01");
    printf(", (%d)\n", mantisse);

    double value = 0.5;
    double res = 1;
    for (int i = 0; i < 23; i++) {
        // Get digit into the mantisse
        res += ((mantisse >> (22 - i)) & 1) * value;
        value /= 2;
    }
    for (int i = 0; i < exponent; i++) {
        res *= 2;
    }

    printf("Value = %f\n", res * sign);

    return 0;
}