c语言版replaceAll方法

在网上看到别人写的replaceAll方法，感觉不太好，所以觉得自己写一个，因为时间仓促，如果有不对的地方请多多指教。

c代码如下：

#include <stdio.h>#include <malloc.h>#include <string.h>char* replaceAll(char* src, char* find, char* replaceWith){//如果find或者replace为null，则返回和src一样的字符串。if(find == NULL || replaceWith == NULL){return strdup(src);}//指向替换后的字符串的head。char* afterReplaceHead = NULL;//总是指向新字符串的结尾位置。char* afterReplaceIndex = NULL;//find字符串在src字符串中出现的次数int count = 0;int i,j,k;int srcLen = strlen(src);int findLen = strlen(find);int replaceWithLen = strlen(replaceWith);//指向src字符串的某个位置，从该位置开始复制子字符串到afterReplaceIndex，初始从src的head开始复制。char* srcIndex = src;//src字符串的某个下标，从该下标开始复制字符串到afterReplaceIndex，初始为src的第一个字符。int cpStrStart = 0;   //获取find字符串在src字符串中出现的次数count = getFindStrCount(src, find);//如果没有出现，则返回和src一样的字符串。if(count == 0){return strdup(src);}    //为新字符串申请内存afterReplaceHead = afterReplaceIndex = (char*)malloc(srcLen + 1 + (replaceWithLen - findLen) * count);    //初始化新字符串内存memset(afterReplaceHead, '\0',sizeof(afterReplaceHead));for(i = 0,j = 0,k = 0;i!=srcLen;i++){//如果find字符串的字符和src中字符串的字符是否相同。if(src[i] == find[j]){//如果刚开始比较，则将i的值先赋给k保存。if(j == 0){k = i;}//如果find字符串包含在src字符串中if(j == (findLen-1)){j = 0;//拷贝src中find字符串之前的字符串到新字符串中strncpy(afterReplaceIndex, srcIndex, i - findLen - cpStrStart + 1);//修改afterReplaceIndexafterReplaceIndex = afterReplaceIndex + i - findLen - cpStrStart + 1;//修改srcIndexsrcIndex = srcIndex + i - findLen - cpStrStart + 1;//cpStrStartcpStrStart = i + 1;//拷贝replaceWith字符串到新字符串中strncpy(afterReplaceIndex, replaceWith, replaceWithLen);//修改afterReplaceIndexafterReplaceIndex = afterReplaceIndex + replaceWithLen;//修改srcIndexsrcIndex = srcIndex + findLen;}else{j++;}}else{//如果find和src比较过程中出现不相等的情况，则将保存的k值还给iif(j != 0){i = k;}j = 0;}}//最后将src中最后一个与find匹配的字符串后面的字符串复制到新字符串中。strncpy(afterReplaceIndex, srcIndex, i - cpStrStart);return afterReplaceHead;}int getFindStrCount(char* src, char* find){int count = 0;char* position =src;int findLen = strlen(find);while((position = strstr(position, find)) != NULL){count++;position = position + findLen;}return count;}int main(void){char* s = "12345345443344341334542345";//调用函数replaceAll，s为源字符串，"345"为需要替换的字符串，”7890“为替换目的字符串。char* r = replaceAll(s, "345", "7890");printf("%s\n",r);//使用replaceAll函数后一定要free掉，因为replace内部会malloc结果字符串的内存。free(r);return 0;}

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