c - 字符串指针问题，未正确指向

Question

这是针对 C 类的。我有以下方法。基本上，它需要一个单词和一个新单词，如果原始单词以辅音开头，则通过将第一个字母移动到末尾(在结束标点符号之前)并在字符串中添加“ay”来创建新单词。我所有的逻辑和案例都有效。我遇到的问题是，当我最后通过 char* newWord 并打印时，该值仍然是原始单词。另外，我自己定义了那些 isConsonant 和 isCapital 等方法。 EndPunc 获取第一个结束标点符号的索引。

例子:word = “猫？!!”newWord = "Atc?!!"

word = "苹果"newWord = "appleay"

但是之后遍历newWord，还是“Cat?!!”或“苹果”。我做错了什么？

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

#define MAXLENGTH 31

char word[31] = "Aat!??!";
char newWord[31] = "";
char* w = word; char* n = newWord;

int isConsonant(char c) // return 1 if consonant, 0 if vowel, -1 if neither
{
    int i = 0;
    while(i < 33)
    {
        if(c == 'a'-i || c == 'e'-i || c == 'i'-i || c == 'o'-i || c == 'u'-i)
            return 0;
        i+=32;
    }
    if(c >= 65 && c <= 122) // its a letter
        return 1;
    else return -1;
}

int isCapital(char c)
{
    if(c >= 97 && c <= 122) // lowerCase
        return 0;
    else return 1; // capital   

}

int isPunctuation(char c)
{
    if(c == '!' || c == ',' || c == '.' || c == '?' || c == ';' || c == ':')
        return 1;

    return 0;   
}

int endPuncIndex(int wordLength, char* word)
{  
    int index = wordLength;

    word += wordLength-1;
    while(isPunctuation(*word--))
        index--;

    return index;
}

int pigLatin(char* word, char* newWord)
{
    int length = 0;
    char* tempWord = word;

    while(*tempWord++ != '\0')
        if(++length > MAXLENGTH)
            return -1;

    tempWord = tempWord-length-1;

    int puncIndex = endPuncIndex(length, word); // get index of last punctuation, if none, index will be length of string

    if(isConsonant(*word) == 1) // first letter is consonant
    {
        char firstLetter = *tempWord;
        char secondLetter = *(++tempWord);
        tempWord++;
        if(isCapital(firstLetter))
        {
            firstLetter += 32; // makes it lowercase, will need to move this to the end
            if(isCapital(secondLetter) == 0) // if second letter isn't capital, make it capital
                secondLetter -= 32;
        }

        int start = 0;
        newWord = &secondLetter;
        newWord++;
        while(start++ < puncIndex-2) // go up to punct index (or end of String if no ending punct)
        {
            newWord = tempWord++;
            newWord++;
        }
        newWord = &firstLetter;
        newWord++;
    }
    else // vowel, just copies the word letter for letter, no insert or shifting
    {
        int start = 0;
        while(start++ < puncIndex) // go up to punct index (or end of String if no ending punct)
        {
            newWord = tempWord++;
            newWord++;
        }
    }

    // add "ay"
    newWord = "a";
    newWord++; 
    newWord = "y";
    newWord++;
    //then add remaining punctuation
    while(puncIndex++ < length)
    {
        newWord = tempWord++;
        newWord++;
    }
    newWord = newWord-(length);
    while(*newWord != '\0')
        printf("%c",*(newWord++));

    return length+3;
}

int main()
{
    pigLatin(w,n);
    printf("\n");
    system("PAUSE");
    return 0;   
}

Answer 1

您正在对纯局部变量进行更改:

    char firstLetter = *tempWord;      /* these are both values not pointers */
    char secondLetter = *(++tempWord); 

更糟糕的是，您正在捕获指向这些局部变量的指针，然后修改它们而不是您要修改的内存:

    newWord = &firstLetter;
    newWord++;

    /* ... */

    newWord = &secondLetter;
    newWord++;

也许你的意思是:

    *newWord = firstLetter; /* store the letter in the position */