【字符串问题】将一个字符串中的单词进行倒置

2013-09-15 14:49:09

将一个字符串中的单词进行倒置，标点符号也倒置，

如输入：hello,nice to meet you!

输出：!you meet to nice,hello

将代码中的while ( *pCur && IsAlphabet(*pCur) )

换成while ( *pCur && *pCur!= ' ' ) 

即可实现翻转单词,标点符号不倒换，

即输入：hello,nice to meet you!

输出：you! meet to hello,nice

注意TestDriver函数中不能定义输入为：

pCHAR srcStrArray[] = {"0123456","i am a good boy!","hello",""};

因为这样的话，每个char*的指针指向的是静态区，静态区的数据就不能改变，在运行时到ReverseString(char *pSrc,size_t begin,size_t end)函数的 *(pStr + index) = *(pSrc + end - index);就会出错，因为该语句试图改变静态区的数据，是不允许的。

这样的错误，类似于下面的：

char *pStr1 = "hello";

char *pStr2[] = "hello";

可以用*pStr2 = ‘a’;改变pStr2指向的字符串，改变后为"aello";

但不可改变pStr1指向的字符串的内容，因此*pStr1 = ‘a’;是不允许的。

---

代码(测试暂未发现错误，欢迎交流指正！)：

#include <iostream>
#include <cassert>
using namespace std;

//翻转首地址为pSrc，索引从begin到end的字符
void ReverseString(char *pSrc,size_t begin,size_t end)
{
    assert(pSrc != NULL);
    char *pStr = (char *)(pSrc + begin);
    char tmpChar;
    size_t index = 0;

    while ( 2 * index < (end - begin) )
    {
        tmpChar = *(pStr + index);
        *(pStr + index) = *(pSrc + end - index);
        *(pSrc + end - index) = tmpChar;

        ++index;
    }
}

//判断字符是否为字母
bool IsAlphabet(char ch)
{
    return ( (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') );
}

//翻转单词
char * ReverseWord(char *pStr)  //不能定义为const
{
    assert(pStr != NULL);
    size_t len = strlen(pStr);

    if (len == 0)  //对空串的处理
    {
        return pStr;
    }

    ReverseString(pStr,0,len - 1);
    cout<<pStr<<endl;

    char *pCur = (char *)pStr;
    int wordBegin = 0;
    int wordEnd = 0;

    while (*pCur)
    {
        wordBegin = pCur - pStr;

        while ( *pCur && IsAlphabet(*pCur) )
        {
            ++pCur;
        }

        wordEnd = pCur - 1 - pStr;  //pCur与pStr相等时，wordEnd定义为size_t会出错

        if (wordBegin < wordEnd)
        {
            ReverseString(pStr,wordBegin,wordEnd);
        }

        ++pCur;
    }
    return pStr;
}


typedef char *  pCHAR;

void TestDriver()
{
    //pCHAR srcStrArray[] = {"0123456","i am a good boy!","hello",""};
    char srcStrArray[][100] = {"0123456","i am a good boy!","hello,nice to meet you!",""};
    size_t arrayLength = 4;

    pCHAR srcStr;

    for (size_t index = 0;index < arrayLength;++index)
    {
        srcStr = srcStrArray[index];
        cout<<"the source string is : "<<srcStr<<endl;

        ReverseWord(srcStr);
        cout<<"the reversed string is : "<<srcStr<<endl<<endl;
    }
}

int main()
{
    TestDriver();
    return 0;
}

测试结果：

the source string is : 0123456
6543210
the reversed string is : 6543210

the source string is : i am a good boy!
!yob doog a ma i
the reversed string is : !boy good a am i

the source string is : hello,nice to meet you!
!uoy teem ot ecin,olleh
the reversed string is : !you meet to nice,hello

the source string is :
the reversed string is :

请按任意键继续. . .

将代码中的while ( *pCur && IsAlphabet(*pCur) )

换成while ( *pCur && *pCur!= ' ' ) 

即可实现翻转单词,标点符号不倒换，测试结果：

the source string is : 0123456
6543210
the reversed string is : 0123456

the source string is : i am a good boy!
!yob doog a ma i
the reversed string is : boy! good a am i

the source string is : hello,nice to meet you!
!uoy teem ot ecin,olleh
the reversed string is : you! meet to hello,nice

the source string is :
the reversed string is :

请按任意键继续. . .