子串删除程序， 抛砖引玉

[华亭真人]

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char *temp;
void del_sub_str(char**s, char* sub)
{
	int len1 = strlen(*s);
	int len2 = strlen(sub);
	if(len1 <  len2)
		return;
	if(strcmp(*s, sub) ==0)
	{
		strcpy(*s, "");
		return;
	}
	strcpy(temp, *s);
	int i ;
	for( i = 0; i < len1 - len2; i++)
	{
		if(*temp == *sub)
		{
			char *t = sub;
			while(*t!='\0'&&(*t++ == *temp++));
			if(*t == '\0')
			{
				break;
			}
		}
		temp++;
	}
	if(i >= len1 - len2 ) 
	{	
		return;
	}
	strcpy((*s)+(len1 - strlen(temp) - len2), temp);
	del_sub_str(s, sub);
}

void main()
{
	char *s = new char[1024];
	temp = new char[1024];
	char *t = temp;
	strcpy(s, "abcdabbaabbkk");
	del_sub_str(&s, "ab");
	printf("%s\n", s);
	delete s;
	delete t; 
}

[昵称很不好取]

怎么还用了一个全局变量

[华亭真人]

呵呵, delete 老是出错，希望大家给出更好的代码。

[qq120848369]

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

char* findSub(char *str,const char *sub)	//找子串
{
	size_t lenStr=strlen(str),lenSub=strlen(sub);

	for(size_t j=0;j<=lenStr-lenSub;++str,++j)
	{
		size_t i;

		for(i=0;sub[i]!=0;++i)
		{
			if(str[i]!=sub[i])
			{
				break;
			}
		}

		if(sub[i]==0)
		{
			return str;
		}
	}

	return NULL;
}

char* delSubStr(char *str,const char *sub)	//用户接口
{
	char *ret=str;

	str=findSub(ret,sub);

	while(str!=NULL)
	{
		char *s;

		for(s=str+strlen(sub);*s!=0;++s)
		{
			*(s-strlen(sub))=*s;
		}

		*(s-strlen(sub))=0;
		str=findSub(ret,sub);
	}

	return ret;
}

int main()
{
	char a[]="aaaaabbbbbbbbcccc";
	char b[]="bc";
	printf("%s\n",delSubStr(a,b));

	return 0;
}

不做什么优化了,就这样能用.

[qq120848369]

提示楼主一点,不知道你关注没有,就是我举的例子,删除后可能还会出现新的sub,所以算法要谨慎,

[we_sky2008]

char * del_substr(char *src, const char *sub)
{
    int len;
    char *dst = src;
    char *temp = src;

    if (src == NULL || sub == NULL)
        return NULL;     
    len = strlen(sub);

    while((temp = strstr(temp, sub)) != NULL)
    {
        strcpy(temp, temp + len);
    }
    return dst;
}

[we_sky2008]

不使用库函数可以这么写：

char * del_substr(char *src, const char *sub)
{   
    char *pslow = src;
    char *pfast = src;
    
    if (src == NULL)
        return NULL;
    if (sub == NULL || !*sub)
        return src;

    for (;;)
    {
        if (*pfast == *sub)
        {    
            char *psrc = pfast;
            const char *psub = sub;

            while (*++psrc == *++psub)
            {
                if (!*psub)
                {
                    *pslow = 0;
                    return src;
                }
            }
            if (!*psub)
                pfast = psrc;
            else
                while(psub-- > sub)
                    *pslow++ = *pfast++;
        }
        else
            if (!(*pslow++ = *pfast++))
                return src;
    }
}

[we_sky2008]

[Quote=引用 5 楼 qq120848369 的回复:]
提示楼主一点,不知道你关注没有,就是我举的例子,删除后可能还会出现新的sub,所以算法要谨慎,
[/Quote]
恩，确实会有这个问题，如果想去掉新出现的子串可以像下面这样：

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

char * del_substr(char *src, const char *sub)
{
    int len;
    char *dst = src;
    char *temp = src;

    if (src == NULL || sub == NULL)
        return NULL;     
    len = strlen(sub);

    while((temp = strstr(src, sub)) != NULL)//搜子串是从头开始搜索
    {
        strcpy(temp, temp + len);
    }
    return dst;
}

int main()
{
    char a[] = "aaaaabbbbbbbbcccc";
    char b[] = "bc";

    printf("%s\n", del_substr(a, b));

    system("pause");
    return 0;
}

[华亭真人]

很好 很强大.