c - C中的加密函数

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enter image description here所以我需要编写一个程序来扫描单词，然后用给定的 key 对它们进行加密( key 在 main 中)。输出应包含加密的单词(加密使用带有单词中字母的 ASCII 值的 key ，因此假设我们有单词 BOOK，那么第一个字母将切换到第 65 位的 key )。我需要将用户给出的单词扫描到字符串中，并将指向这些字符串的指针保存到数组 char *words 中。然后我加密它们并按如下方式打印它们:

words[0][0-n]\n ('n' is the length of the word=the same length as original but encr)
words[1][0-k]\n ('k' is the length of the word=the same length as original but encr)

。。。我是编程新手，并且在使用这些字符串时遇到问题..帮助

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

#define KEY_SIZE 256



char encrypt_char(unsigned char key[KEY_SIZE], char ch);
int read_words(char* words[], int size, int max_str_len);
void encrypt_words(char* words[], int num_words, unsigned char key[KEY_SIZE]);




   int main()
{
    int i=0,j=0;
    unsigned char key[KEY_SIZE] = {
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I', 'O', 'P', 'A', 'S', 'D',
        'F', 'G', 'H', 'J', 'K', 'L', 'Z', 'X', 'C', 'V', 'B', 'N', 'M'};

    char* words[1000];      //the words must bee a 2D array beacause its a string array .
    int num_words=read_words(words,1000,100);
    printf("number of words =%d",num_words);/////check
    encrypt_words(words,num_words,key);
    while (words[i][j]!=0)
    {
        printf("%c",words[i][j]);
        i++,j++;
    }
    return 0;
}






char encrypt_char(unsigned char key[KEY_SIZE], char ch)
{
    int temp=ch;
    return key[temp];
}





int read_words(char* words[], int size, int max_str_len)
{
    printf("in the read words func\n"); ///check
    int i=0,words_count=0;
    char* temp=malloc((max_str_len+1)*sizeof(char));
    if (temp==NULL)
    {
        printf("Memory allocation failure\n");
        free(temp);
        return 0;
    }
    printf("passed the fail test\n"); ////check
    while ( scanf("%s",temp)==1&&words_count<size)
    {
        printf("in the while \n");
        int length=strlen(temp);
        char* the_word=malloc((length+1)*sizeof(char));
        strcpy(the_word, temp);
        words[i]=(char*)the_word;
        i++;
        words_count++;
        printf("the i=%d          words count=%d          words[%d]=%s    \n",i,words_count,i,&words[i]);/////////check
    }
    printf("WORDS COUNT IS=%d\n",words_count);
return words_count;

}


void encrypt_words(char* words[], int num_words, unsigned char key[KEY_SIZE])
{
    int i=0,j=0;
    while (words[i][j]!=0&&i<num_words)
    {
        char temp=words[i][j];
        words[i][j]=encrypt_char(key,temp);
        i++,j++;
    }
}

编译器消息:

-------------- Build: Debug in hw4q2 (compiler: GNU GCC Compiler)---------------

mingw32-gcc.exe -Wall -Werror -pedantic -ansi -W -O -g -pedantic-errors -std=c99  -c "C:\Users\Anton\Desktop\C projects\hw4q2\hw4q2.c" -o obj\Debug\hw4q2.o
mingw32-g++.exe  -o hw4q2.exe obj\Debug\hw4q2.o   
Output file is hw4q2.exe with size 73.25 KB
Process terminated with status 0 (0 minute(s), 0 second(s))
0 error(s), 0 warning(s) (0 minute(s), 0 second(s))

Answer 1

您的问题出在这段代码中:

while (words[i][j]!=0)
{
    printf("%c",words[i][j]);
    i++,j++;
}

此处同时递增 i 和 j。因此，你们都可以一步跳到下一个字母和下一个字符串。如果您跳出字符串终止符，则会失败。

试试这个:

for (i=0; i<num_words; ++i)
{
    printf("%s\n",words[i]);
}

类似的问题在这里:

void encrypt_words(char* words[], int num_words, unsigned char key[KEY_SIZE])
{
    int i=0,j=0;
    while (words[i][j]!=0&&i<num_words)
    {
        char temp=words[i][j];
        words[i][j]=encrypt_char(key,temp);

        i++,j++;   // Ups...
    }
}

您需要先完成一个字符串(即仅递增 j)，然后移动到下一个字符串(即递增 i)。

类似于:

void encrypt_words(char* words[], int num_words, unsigned char key[KEY_SIZE])
{
    int i=0,j=0;
    for (i=0; i<num_words; ++i)
    {
        j = 0;
        while (words[i][j]!=0)
        {
            char temp=words[i][j];
            words[i][j]=encrypt_char(key,temp);
            j++;
        }
    }
}