c - 算术移位不适用于负数输入？知道我在这里做错了什么吗？

Question

// 1.5 Exercise 6.cpp : main project file.

#include "stdafx.h"
#include <stdio.h>

int sra(int x, int n);

int main()
{
    int intInputNum;

    int finalValue1;
    int finalValue2;

    printf("Please enter a integer and program will shift the integer 2 places to right,\n it will give value for both arithmetic as well as Logical shift\n");
    scanf("%d",&intInputNum);

    finalValue1 = intInputNum >> 2;

    finalValue2 = sra(intInputNum, 2);

    printf("Logical %d \n Arithmetic %d\n", finalValue1, finalValue2);

    return 0;
}


int sra(int x, int k)
{
    int xsrl = (unsigned)x >> k;
    unsigned mask = k ? ((1 << (8 * sizeof(int)-k)) - 1) : 0;
    return (x < 0) ? mask | xsrl : xsrl;
}

示例运行:

Please enter a integer and program will shift the integer 2 places to right, it will give value for both arithmetic as well as Logical shift-500Logical -125Arithmetic 1073741823

为什么这没有显示正确的值？

Answer 1

该标准不保证任何事情(即，要么是 << 案例中的未定义行为，要么是(您的)>> 案例中定义的实现)的转变对负左侧 (LHS) 参数的运算。