unsigned char plain[] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0

unsigned char plain[] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88};

这是一个长度为9的无符号字符数组。每个元素占一个字节，用16进制表示。

unsigned char是C语言中的数据类型，表示一个字节的无符号整数，取值范围是0到255。在这个例子中，数组中的元素都是16进制的数字，可以转换成十进制为{0, 17, 34, 51, 68, 85, 102, 119, 136}。

这个数组可以用来存储任意二进制数据，比如字节流、加密密钥等。

在加密和编码中，使用unsigned char数组可以很方便地处理字节，进行位操作和数据处理。

在C语言中，unsigned char类型常常用来表示字节数据，在数据传输、加密算法、图像处理等方面都有广泛的应用。unsigned char的大小正好是一个字节，可以很方便地表示8位二进制数据。

总之，unsigned char数组在C语言中是一个很常用的数据类型，用来表示字节数据，进行各种数据操作和处理。

相关问题

单片机，修改以下代码#include<reg52.h> unsigned char cols[]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xE7,0xE3,0xE7,0xE7,0xE7,0xE7,0xE7,0xC3, 0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF}; unsigned char p_i =0;//p_i=0表示显示第一幅图像 void main(){ //定时器1和中断 TMOD = 0x10; TR1=1; TH1=0xfc; TL1=0x67; EA=1; ET1=1; while(1); } void interrupt_T1() interrupt 3{ static unsigned char row_i=0;//row_i=0表示选中点阵第一行 static unsigned int cnt=0;//cnt=1表示进过1ms，用于点阵行的切换 static unsigned int p_cnt=0;//p_cnt=1表示进过1ms，用于图像的切换 TH1=0xfc; TL1=0x67; P0 = 0xff;//消隐 cnt++; p_cnt++; if(cnt==1){ cnt=0; row_i++; if(row_i==8){ row_i =0; } } if(p_cnt==10){ p_cnt=0; p_i++; if(p_i==17){ p_i =0; } } switch(row_i){ case 0:P2 =0x01;P0 = cols[0+p_i];break; case 1:P2=0x02;P0 = cols[1+p_i];break; case 2:P2 =0x04;P0 = cols[2+p_i];break; case 3:P2=0x08;P0 = cols[3+p_i];break; case 4:P2 =0x10;P0 = cols[4+p_i];break; case 5:P2=0x20;P0 = cols[5+p_i];break; case 6:P2 =0x40;P0 = cols[6+p_i];break; case 7:P2=0x80;P0 = cols[7+p_i];break; default:break; plaintext Copy code } }实现8*8点阵9到0倒序秒表

以下是修改后的代码：

#include<reg52.h>

unsigned char cols[]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xE7,0xE3,0xE7,0xE7,0xE7,0xE7,0xE7,0xC3,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};

unsigned char p_i =0;//p_i=0表示显示第一幅图像

unsigned char sec_cnt = 0; // 秒计数器
unsigned char sec_num = 9; // 当前显示的秒数

void main(){
//定时器1和中断
TMOD = 0x10;
TR1=1;
TH1=0xfc;
TL1=0x67;
EA=1;
ET1=1;
while(1);
}

void interrupt_T1() interrupt 3{
static unsigned char row_i=0;//row_i=0表示选中点阵第一行
static unsigned int cnt=0;//cnt=1表示进过1ms，用于点阵行的切换
static unsigned int p_cnt=0;//p_cnt=1表示进过1ms，用于图像的切换
TH1=0xfc;
TL1=0x67;
P0 = 0xff;//消隐
cnt++;
p_cnt++;
if(cnt==1){
cnt=0;
row_i++;
if(row_i==8){
row_i =0;
}
}
if(p_cnt==10){
p_cnt=0;
p_i++;
if(p_i==17){
p_i =0;
}
}
switch(row_i){
case 0:P2 =0x01;P0 = cols[0+p_i];break;
case 1:P2=0x02;P0 = cols[1+p_i];break;
case 2:P2 =0x04;P0 = cols[2+p_i];break;
case 3:P2=0x08;P0 = cols[3+p_i];break;
case 4:P2 =0x10;P0 = cols[4+p_i];break;
case 5:P2=0x20;P0 = cols[5+p_i];break;
case 6:P2 =0x40;P0 = cols[6+p_i];break;
case 7:P2=0x80;P0 = cols[7+p_i];break;
default:break;
}

// 每隔1秒更新秒数
if (sec_cnt == 100) {
sec_cnt = 0;
if (sec_num == 0) {
sec_num = 9;
} else {
sec_num--;
}

// 更新cols数组，显示倒序秒数
for (int i = 16; i < 24; i++) {
cols[i] = cols[i] & ~(1 << sec_num);
}
}

sec_cnt++;
}

在原有的代码基础上，我们添加了两个变量sec_cnt和sec_num，分别用于计数和记录当前秒数。在T1中断中，我们每隔1秒更新一次秒数，并更新cols数组，将倒序秒数显示在点阵上。

给出一个完整的c语言程序，让其能实现DES算法。满足以下要求：每个学生输入自己的学号和“班级”，给出5种密钥的加密结果。从0x00000010-0x0000001F中选5种密钥，或随机生成16个密钥。

由于DES算法的实现比较复杂，需要大量的代码，我这里仅提供一个简化版的DES算法实现，仅供参考。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define ENCRYPT_MODE 0
#define DECRYPT_MODE 1

typedef unsigned char byte;
typedef unsigned int uint;

// Initial Permutation Table
const byte IP[] = { 58, 50, 42, 34, 26, 18, 10, 2,
                    60, 52, 44, 36, 28, 20, 12, 4,
                    62, 54, 46, 38, 30, 22, 14, 6,
                    64, 56, 48, 40, 32, 24, 16, 8,
                    57, 49, 41, 33, 25, 17, 9, 1,
                    59, 51, 43, 35, 27, 19, 11, 3,
                    61, 53, 45, 37, 29, 21, 13, 5,
                    63, 55, 47, 39, 31, 23, 15, 7 };

// Final Permutation Table
const byte FP[] = { 40, 8, 48, 16, 56, 24, 64, 32,
                    39, 7, 47, 15, 55, 23, 63, 31,
                    38, 6, 46, 14, 54, 22, 62, 30,
                    37, 5, 45, 13, 53, 21, 61, 29,
                    36, 4, 44, 12, 52, 20, 60, 28,
                    35, 3, 43, 11, 51, 19, 59, 27,
                    34, 2, 42, 10, 50, 18, 58, 26,
                    33, 1, 41, 9, 49, 17, 57, 25 };

// Permuted Choice 1 Table
const byte PC1[] = { 57, 49, 41, 33, 25, 17, 9,
                     1, 58, 50, 42, 34, 26, 18,
                     10, 2, 59, 51, 43, 35, 27,
                     19, 11, 3, 60, 52, 44, 36,
                     63, 55, 47, 39, 31, 23, 15,
                     7, 62, 54, 46, 38, 30, 22,
                     14, 6, 61, 53, 45, 37, 29,
                     21, 13, 5, 28, 20, 12, 4 };

// Permuted Choice 2 Table
const byte PC2[] = { 14, 17, 11, 24, 1, 5, 3, 28,
                     15, 6, 21, 10, 23, 19, 12, 4,
                     26, 8, 16, 7, 27, 20, 13, 2,
                     41, 52, 31, 37, 47, 55, 30, 40,
                     51, 45, 33, 48, 44, 49, 39, 56,
                     34, 53, 46, 42, 50, 36, 29, 32 };

// Expansion (E) Table
const byte E[] = { 32, 1, 2, 3, 4, 5, 4, 5,
                   6, 7, 8, 9, 8, 9, 10, 11,
                   12, 13, 12, 13, 14, 15, 16, 17,
                   16, 17, 18, 19, 20, 21, 20, 21,
                   22, 23, 24, 25, 24, 25, 26, 27,
                   28, 29, 28, 29, 30, 31, 32, 1 };

// Substitution Boxes (S-boxes)
const byte S[8][4][16] = {
    // S1
    {
        {14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7},
        {0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8},
        {4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0},
        {15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13}
    },
    // S2
    {
        {15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10},
        {3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5},
        {0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15},
        {13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9}
    },
    // S3
    {
        {10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8},
        {13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1},
        {13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7},
        {1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12}
    },
    // S4
    {
        {7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15},
        {13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9},
        {10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4},
        {3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}
    },
    // S5
    {
        {2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9},
        {14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6},
        {4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14},
        {11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3}
    },
    // S6
    {
        {12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11},
        {10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8},
        {9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6},
        {4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13}
    },
    // S7
    {
        {4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1},
        {13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6},
        {1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2},
        {6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12}
    },
    // S8
    {
        {13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7},
        {1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2},
        {7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8},
        {2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11}
    }
};

// Permutation (P) Table
const byte P[] = { 16, 7, 20, 21, 29, 12, 28, 17,
                   1, 15, 23, 26, 5, 18, 31, 10,
                   2, 8, 24, 14, 32, 27, 3, 9,
                   19, 13, 30, 6, 22, 11, 4, 25 };

// Initial Permutation Inverse Table
const byte IP_INV[] = { 40, 8, 48, 16, 56, 24, 64, 32,
                        39, 7, 47, 15, 55, 23, 63, 31,
                        38, 6, 46, 14, 54, 22, 62, 30,
                        37, 5, 45, 13, 53, 21, 61, 29,
                        36, 4, 44, 12, 52, 20, 60, 28,
                        35, 3, 43, 11, 51, 19, 59, 27,
                        34, 2, 42, 10, 50, 18, 58, 26,
                        33, 1, 41, 9, 49, 17, 57, 25 };

// Rotation Table for key schedule
const byte R[] = { 1, 2, 4, 6, 8, 10, 12, 14, 15, 17, 19, 21, 23, 25, 27, 28 };

// Key Schedule
void key_schedule(byte key[], byte subkeys[][6]) {
    byte C[28], D[28], CD[56];
    byte K[48];

    // Permuted Choice 1
    for (int i = 0; i < 28; i++) {
        C[i] = key[PC1[i] - 1];
        D[i] = key[PC1[i + 28] - 1];
    }

    // Generate 16 subkeys
    for (int i = 0; i < 16; i++) {
        // Rotate C and D
        byte tmp1 = C[0], tmp2 = D[0];
        for (int j = 0; j < 27; j++) {
            C[j] = C[j + 1];
            D[j] = D[j + 1];
        }
        C[27] = tmp1;
        D[27] = tmp2;

        // Permuted Choice 2
        for (int j = 0; j < 48; j++) {
            int idx = PC2[j] - 1;
            if (idx < 28) {
                K[j] = C[idx];
            }
            else {
                K[j] = D[idx - 28];
            }
        }

        memcpy(subkeys[i], K, 6);
    }
}

// Expansion (E) Function
void expand(byte R[], byte E_R[]) {
    for (int i = 0; i < 48; i++) {
        E_R[i] = R[E[i] - 1];
    }
}

// XOR Function
void xor(byte a[], byte b[], byte c[], int len) {
    for (int i = 0; i < len; i++) {
        c[i] = a[i] ^ b[i];
    }
}

// Substitution (S) Function
void substitute(byte B[], byte S_B[]) {
    for (int i = 0; i < 8; i++) {
        int row = (B[i * 6] << 1) + B[i * 6 + 5];
        int col = (B[i * 6 + 1] << 3) + (B[i * 6 + 2] << 2) + (B[i * 6 + 3] << 1) + B[i * 6 + 4];
        int val = S[i][row][col];
        S_B[i * 4] = (val & 8) >> 3;
        S_B[i * 4 + 1] = (val & 4) >> 2;
        S_B[i * 4 + 2] = (val & 2) >> 1;
        S_B[i * 4 + 3] = val & 1;
    }
}

// Permutation (P) Function
void permute(byte B[], byte P_B[]) {
    for (int i = 0; i < 32; i++) {
        P_B[i] = B[P[i] - 1];
    }
}

// Initial Permutation (IP) Function
void initial_permutation(byte plaintext[], byte IP_text[]) {
    for (int i = 0; i < 64; i++) {
        IP_text[i] = plaintext[IP[i] - 1];
    }
}

// Final Permutation (FP) Function
void final_permutation(byte ciphertext[], byte FP_text[]) {
    for (int i = 0; i < 64; i++) {
        FP_text[i] = ciphertext[FP[i] - 1];
    }
}

// DES Round Function
void round_func(byte plaintext[], byte key[], byte ciphertext[]) {
    byte L[32], R[32], E_R[48], K[48], B[8], S_B[32], P_B[32];

    // Split plaintext into L and R
    memcpy(L, plaintext, 32);
    memcpy(R, plaintext + 32, 32);

    // Expand R to 48 bits
    expand(R, E_R);

    //