C++编写一个字符串置换函数

c++编程：编写一个字符串置换函数 void repstr(char * source, char * str_s, char * str_d)，功能是将source 字符串中的str_s子串替换成字符串 str_d

//字符串替换函数，在字符串 string 中查找 source， 找到则替换为destination，找不到则返回NULL
static char * replace_string (char * string, const char * source, const char * destination )
{
char* sk = strstr (string, source);
if (sk == NULL) return NULL;

char* tmp;
size_t size = strlen(string)+strlen(destination)+1;

char* newstr = (char*)calloc (1, size);
if (newstr == NULL) return NULL;

char* retstr = (char*)calloc (1, size);
if (retstr == NULL)
{
free (newstr);
return NULL;
}

snprintf (newstr, size-1, "%s", string);
sk = strstr (newstr, source);

while (sk != NULL)
{
int pos = 0;
memcpy (retstr+pos, newstr, sk - newstr);
pos += sk - newstr;
sk += strlen(source);
memcpy (retstr+pos, destination, strlen(destination));
pos += strlen(destination);
memcpy (retstr+pos, sk, strlen(sk));

tmp = newstr;
newstr = retstr;
retstr = tmp;

memset (retstr, 0, size);
sk = strstr (newstr, source);
}
free (retstr);
return newstr;

}

bool isincluded(const char *lpszres, const char *lpszdst) {  const char *p1 = lpszres;  const char *p2 = lpszdst;  int nreslen = strlen(lpszres);  int ndeslen = strlen(lpszdst);  if(nreslen < ndeslen) return false;  while (p1 != lpszres+nreslen)  {   int nlen = strlen(p1);   if (nlen < ndeslen) return false;   const char *p3 = p1;   p2 = lpszdst;   while (p3 != p1+ndeslen)   {    if(*p3 == *p2)    {     ++p3;     ++p2;     continue;    }    else     break;   }   if(p3 == p1+ndeslen)    return true;   ++p1;  }  return false; }

strlen 还是能用不？？

//刚写的code，测试通过，用C++写的 //如果有疑问，欢迎交流 //如果source里有多个str_s字串，那么都会将其替换掉 //这里的条件逻辑，可能有点儿复杂，设定一些状态，用flag表示 //flag: 0表示要往tmp_source里插入字符 //flag: 1表示当前找到了可能是str_s的字串 #include<iostream> #include<string> using namespace std; #define N 1000 void repstr(char * source, char * str_s, char * str_d){ int src_len = strlen(source); char *tmp_source = new char[N]; //创建一个新串，保存替换后的结果 int flag = 0; int cur_idx = 0, str_d_idx = 0, str_s_idx = 0, tmp_idx = 0; while(source[cur_idx] != '\0'){ if(flag == 0 && source[cur_idx] == str_s[0]){ flag = 1; str_s_idx++; cur_idx++; } if(flag == 1){ if(str_s[str_s_idx] == '\0'){ str_d_idx = 0; // while(str_d[str_d_idx]!='\0'){ tmp_source[tmp_idx] = str_d[str_d_idx]; tmp_idx++; str_d_idx++; } str_s_idx = 0; flag = 0; }else if(str_s[str_s_idx] == source[cur_idx]){ str_s_idx++; cur_idx++; }else if(str_s[str_s_idx] != source[cur_idx]){ flag = 0; cur_idx = cur_idx - str_s_idx; str_s_idx = 0; } } if(flag == 0&&source[cur_idx]!='\0'){ tmp_source[tmp_idx] = source[cur_idx]; tmp_idx++; cur_idx++; } } tmp_source[tmp_idx] = '\0'; tmp_idx = 0; while(tmp_source[tmp_idx]!='\0'){ source[tmp_idx] = tmp_source[tmp_idx]; tmp_idx++; } source[tmp_idx] = 0; delete tmp_source; } int main(){ char source[1000] = "word hellonicehelotoyouhellowhy"; cout<<source<<endl; char *src_s = "hello"; char *tar_s = "ChinaFootball"; repstr(source, src_s, tar_s); cout<<source<<endl; return 0; }