C语言问题 uint32_t提取浮点数

请问这个要怎么解决？在//REPLACE ME WITH YOUR CODE那写内容，在sign_flip.c上写内容，按照要求来写，要写main函数，就像最下面的图片的例子那样。在可以用下面的例子来测试是否正确。原题为英文，有机翻。da佬编写1下，蟹蟹大lao。题目如下

sign_flip.c内容
#include "sign_flip.h"

// given the 32 bits of a float return it with its sign flipped
uint32_t sign_flip(uint32_t f) {
    return 42; // REPLACE ME WITH YOUR CODE
}


```c
sign_flip.h内容
#ifndef SIGN_FLIP_H
#define SIGN_FLIP_H

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

/// We use `union overlay' to obtain the raw bits of a `float'-type
/// value, by storing the `float' in the `f' field and then using the
/// `u' field to obtain the bits.
union overlay {
    float f;
    uint32_t u;
};

uint32_t sign_flip(uint32_t f);

#endif

-inf是什麽意思？