在 C 中以 IEEE 标准打印浮点数（十六进制）

Question

I want to print the hexadecimal value of two floating point numbers in the IEEE standard representation (sign, 8 bit exponent, 23 bit mantissa). My problem is that the numbers that I random generate are super big (for example: -26815622280406798000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000) without any numbers after the point (only 0) and with sign.

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#include<math.h>

float RandVectorGen(void);

int main () {

    srand(time(NULL));

    float Vectors_A = 0, Vectors_B = 0, Vectors_SUM = 0; 

            for(int i = 0; i <= 20; ++i) {
                
                Vectors_A = RandVectorGen();      //Genera 20 vettori tra 100 e 0
                Vectors_B = RandVectorGen();

                printf("Vettore %d_A: %x  =>  %.6f\n", i, Vectors_A, Vectors_A);
                printf("Vettore %d_B: %x  =>  %.6f\n", i, Vectors_B, Vectors_B);

                Vectors_SUM = Vectors_A + Vectors_B;            

                printf("Somma tra i due vettori: %x  =>  %.6f\n", Vectors_SUM, Vectors_SUM);

                puts(" ");

                }

    return 0;

}

float RandVectorGen (void) {

    
    unsigned int Vector1, Vector2;
    float RandomVector = ((float)Vector1 / (float)Vector2) * fabs(sin(rand() % 10));

        Vector1 = (rand() % 30);
        Vector2 = (rand() % 30);

    return RandomVector;
}

Answer 1

In the absence of flow control, C runs from top to bottom. So when you initialize RandomVector using two uninitialized variables, you get Undefined Behavior. It does not matter that you later assign two values to Vector 1 and Vector2 .

Answer 2

Your RandomVector is random in the sense that it is based on uninitialized values, which is undefined behavior. You only assign values to Vector1 and Vector2 after that, but you never use those. You should try it like this:

float RandVectorGen (void)
{
    unsigned int Vector1, Vector2;
    float RandomVector;

    Vector1 = (rand() % 30);
    Vector2 = (rand() % 30);
    
    RandomVector = ((float)Vector1 / (float)Vector2) * fabs(sin(rand() % 10));

    return RandomVector;
}