如何扭转4字节的无符号整数的？ [英] How to reverse the 4 bytes of an unsigned integer?

问题描述

我想用'«'和'»'扭转的无符号整数，位元与和OR（安培;和|），但无法弄清楚如何做到这一点<。 / p>

我已经有;

  INT主（INT ARGC，字符** argv的）{
    无符号整型getal;
    scanf函数（％i的，＆安培; getal）;
    的printf（％X \\ n，getal）;
    返回0;
}
 

用户输入：现在0xaabbccdd，输出：AABBCCDD，它应该输出DDCCBBAA

我也试过;

  INT主（INT ARGC，字符** argv的）{
    无符号整型getal;
    无符号整数X;
    scanf函数（％i的，＆安培; getal）;
    INT I;
    对于（I = 0; I＆下; 32; ++ i的）{
        getal＆所述;＆下; = 1;
        getal | =（X安培; 1）;
        X  -  GT;＆GT; = 1;
        的printf（％X \\ n，getal）;
    }
    返回0;
}
 

但结果却是完全不同的。

解决方案

试试这个：

  INT getal; //这是普通的整数
INT逆转; //这是getal反向/ *获取数字形式的控制台这里* /字符* N1，N2 *;
N1 =（字符*）及getal;
N2 =（字符*）及反;*（N 2 + 0）= *（N1 + 3）; //或N2 [0] = N1 [3];
*（N + 1）= *（N1 + 2）; //或N2 [1] = N1 [2];
*（N2 + 2）= *（N1 + 1）; //或N2 [2] = N1 [1];
*（N 2 + 3）= *（N1 + 0）; //或N2 [3] = N1 [0];/ *打印逆转这里* /
 

请注意： *（A + B）= A [B] = B [A]

I am trying to reverse the unsigned integer by using the '«' and '»', and bitwise 'AND' and 'OR' (& and |), but can't figure out how to do this.

What I already have;

int main(int argc, char** argv) {
    unsigned int getal;
    scanf("%i", &getal);
    printf("%X\n", getal);
    return 0;
}

User input: 0xaabbccdd, output now: AABBCCDD, what it should output DDCCBBAA

I also tried;

int main(int argc, char** argv) {
    unsigned int getal;
    unsigned int x;
    scanf("%i", &getal);
    int i;
    for (i = 0; i < 32; ++i) {
        getal <<= 1;
        getal |= (x & 1);
        x >>= 1;
        printf("%X\n", getal);
    }
    return 0;
}

but the result was completely different.

解决方案

Try this:

int getal;     // this is regular integer number
int reversed;  // this is reverse of getal

/* get number form console here */

char *n1, *n2;
n1 = (char *)&getal;
n2 = (char *)&reversed;

*(n2 + 0) =  *(n1 + 3);  // or n2[0] = n1[3];
*(n2 + 1) =  *(n1 + 2);  // or n2[1] = n1[2];
*(n2 + 2) =  *(n1 + 1);  // or n2[2] = n1[1]; 
*(n2 + 3) =  *(n1 + 0);  // or n2[3] = n1[0];

/* print reversed here */

Note: *(a + b) = a[b] = b[a]

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