转换4个字节CHAR在C INT32 [英] Convert 4 bytes char to int32 in C

问题描述

我先转换成一个Int32数为char [4]数组，然后通过为（int *）数组转换回INT32，但数量并不像以前一样：

I first convert an int32 number to char[4] array, then convert the array back to int32 by (int *), but the number isn't the same as before:

unsigned int num = 2130706432;
unsigned int x;
unsigned char a[4];

a[0] = (num>>24) & 0xFF;
a[1] = (num>>16) & 0xFF;
a[2] = (num>>8) & 0xFF;
a[3] = num & 0xFF;

x = *(int *)a;
printf("%d\n", x);

输出为127。如果我设置NUM = 127，输出为2130706432。
没有任何人有想法？

the output is 127. And if I set num = 127, the output is 2130706432. Does anyone have ideas?

推荐答案

反向顺序的一个[]索引，例如，。一个[0] - >一个[3]

Reverse the order of the a[] indexes, e.g,. a[0] -> a[3]

我觉得你有相反的字节顺序。

I think you have the endianness in reverse.

试试这个：

a[3] = (num>>24) & 0xFF;
a[2] = (num>>16) & 0xFF;
a[1] = (num>>8) & 0xFF;
a[0] = num & 0xFF;

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