c - Cで置換関数を書く方法

Question

iの- 番目のバイトがxに置き換えられた値を返す関数を作成しますb。

unsigned replace_f (unsigned x, int i, unsigned char b){

}

元：replace_f(0x12345678, 2, 0xBC) --> 0x12BC5678

Answer 1

試しませんでしたが、これはうまくいく可能性があります：

unsigned replace_f (unsigned x, int i, unsigned char b){
    char *c;

    c = (char *)&x;
    c[i] = b;
    return x;
}

Answer 2

unsigned replace_f (unsigned x, int i, unsigned char b){
    unsigned char *place = (unsigned char*)&x;
    place[sizeof(int)-i] = b;
    return x;
}

リトルエンディアンを想定