字符串逆置（轉載）

字符串逆置 (2011-02-18 11:23:37)

轉載地址：http://blog.sina.com.cn/s/blog_705eb43a0100ptl7.html

標籤： it 分類： 筆試小程序

將字符串逆置："i come from tianjin."-->“tianjin. from come i”
思路：先將整個字符串逆置，然後將每個單詞逆置
          原始字符串              s=i come from tianjin.
          將整個字符串逆置   s=.nijnait morf emoc i
          再將每個單詞逆置   s=tianjin. from come i
程序：

#cat string_reverse.c
*******************************************************************************
#include <stdio.h>
#include <string.h>


void reverse(char *s, int begin, int end)
{
        int i,j;
        for(i = begin, j = end - 1; i < j; i ++, j --)
        {
                s[i] = s[i] ^ s[j];
                s[j] = s[i] ^ s[j];
                s[i] = s[i] ^ s[j];
        }
}


void reverse2(char *s,int begin, int end)
{
        int len=strlen(s);
        int i,j,t;
        for(i = begin, j = end - 1; i < j; i ++, j --)  
        {
                t=s[i];
                s[i]=s[j];
                s[j]=t;
        }
}


int main()
{
        char s[] = "i come from tianjin.";
        int i,j;
        printf("the original s=%s\n",s);
       
        reverse2(s, 0, strlen(s));
        printf("the string after revese the whole sentence s=%s\n",s);
       
        for(i = 0; i < strlen(s);)
        {
                for(j = i; j < strlen(s) && s[j] != ' '; j ++)
                        ;
                reverse2(s, i, j);
                i = j + 1;
        }


        printf("the string after reverse each word s=%s\n",s);
        return 0;
}
****************************************************************************************************
 結果：
./string_reverse
the original s=i come from tianjin.
the string after revese the whole sentence s=.nijnait morf emoc i
the string after reverse each word s=tianjin. from come i








附錄：abcd->dcba
程序1：
******************************************************************************
#include <stdio.h>
#include <string.h>
#include <malloc.h>


int main()
{
        char *src = "abcd";
        int len = strlen(src);
        char *dest = (char *)malloc(len+1);
        char *d = dest;
        char *s = &src[len-1];
        while(len-- != '\0')
                *d++=*s--;
        *d='\0';
        printf("dest=%s\n",dest);
        free(dest);
        return 0;
}
***************************************************************************
程序2：
*****************************************************************************
char * reverse（char *s)
{
 int len=strlen(s);
 int i,t;
 for(i=0;i<len/2;i++)
   {
          t=s[i];
         s[i]=s[len-1-i];
          s[len-1-i]=t;
    }
 return s;
}