c - 陷入无限循环，不知道我做错了什么

Question

程序可以编译，但是当我尝试使用它时，出现无限循环。我哪里做错了。我将评论添加到我想要完成的任务中。

我尝试将其更改为 for 循环，但仍然遇到问题。我想我应该坚持使用 while 循环来完成我想要完成的任务。

  //Declare the arrays to hold the strings
  char str[21], vowels[21], consonants[21];
int i=0;

  //Declare the pointers
  char *strPointer, *vowelPointer, *consonantPointer;

  //Print out the prompt to the user
  printf("Enter a string (20 characters maximum): ");

  //Scan the user input into str
  //Only allow 20 characters
  scanf("%s", str);

  //Set strPointer to the beginning of the user's string
  strPointer = str;

  //Set vowelPointer to the beginning of the vowels string
  vowelPointer = vowels;

  //Set consonantPointer to the beginning of tht consonant string
  consonantPointer = consonants;

  //Loop through the user's string until the end of the string
  while(*strPointer !='\0')
  {
    //Check if what strPointer is pointing to is a vowel
    if(strPointer[i]=='A'||strPointer[i]=='a'||strPointer[i]=='E'||strPointer[i]=='e'||strPointer[i]=='I'||strPointer[i]=='i'||strPointer[i]=='O'||strPointer[i]=='o'||strPointer[i]=='U'||strPointer[i]=='u')
    {

      //Move the letter from strPointer to vowelPointer
    strPointer=vowelPointer
      ;

      //Move the vowelPointer
    vowelPointer=vowels
      ;

    }
    else
    {

      //Move the letter from strPointer to consonantPointer
    strPointer=consonantPointer
      ;

      //Move the consonantPointer
     consonantPointer=consonants
      ;

    }

    //Move the strPointer
    strPointer=str;
  }

  //Add null terminators where appropriate
  strPointer[21]='\0';
  str[21]='\0';

  //Set the vowel and consonant pointers back to the beginning of their strings
  vowelPointer[0];
  consonantPointer[0];

  //Print the original string and the resulting vowel and consonant strings
  printf("Original string: %s\n", str);
  printf("%s\n", vowelPointer);
  printf("%s\n", consonantPointer);

最后的 printf 语句对输出进行了解释。输入字符串，重新打印，元音和辅音分开并列出。

Answer 1

我想提出一些建议来帮助您。

首先，当您扫描用户输入时，明智的做法是使用缓冲区。然后，将缓冲区的内容 strcpy 到 char 数组中。这将有助于防止溢出。有关此主题的更多详细信息，请参阅下面的代码。

其次，您可以使用 for 循环来迭代每个字母。我希望我的回答能帮助您理解我的意思。

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

int main(void)
{

    //Declare the arrays to hold the strings
     char c, str[21], vowels[21], consonants[21], buffer[21];
     int i = 0, j = 0, h = 0;

     //Declare the pointers
     char *strPointer, *vowelPointer, *consonantPointer;

     //Print out the prompt to the user
     printf("Enter a string (20 characters maximum): ");

     //Scan the user input into str
     scanf("%s", buffer);

     // Copy the buffer into the str
     strcpy(str, buffer);

     // go letter by letter checking if it is a vowel or consonant
     for (int i = 0; str[i]; i++)
     {
         // make the character uppercase
         c = toupper(str[i]);

         // if the letter is a vowel add the letter to the vowel array, 
         // then increase the position
         if (c == 'A' || c == 'E' || c == 'I' || c == 'O' || c == 'U')
             vowels[j++] = str[i];
         else
            // add the letter to the consonants array, then increase the position
            consonants[h++] = str[i];
     }

     // properly terminate the strings
     vowels[j] = '\0';
     consonants[h] = '\0';

     //Print the original string and the resulting vowel and consonant strings
     printf("Original string: %s\n", str);
     printf("%s\n", vowels);
     printf("%s\n", consonants);

    return 0;
}