字符串替换（新开辟空间）

 #include <iostream>

#include <string.h>

using namespace std;

char* replace_my(char* str, char c, const char* rc) // 调用函数前，保证str能展开空间

{ char* ret = str;

char* cp = str; size_t cnt = 0;

 int rcsize = (int)strlen(rc);

while (*cp) { if (*cp == c)

 cnt++; // 统计找到 c 的次数 ++cp;

 }

if (cnt <= 0) // 没找到 c

return ret; cp = str;

int bufsize = strlen(str) + rcsize * cnt + 1;

 char * buf = new char[bufsize]; // 建立缓冲区buf

char * ps = buf; while (*cp) { *ps = *cp;

if (*cp == c) { // 替换字符 c 为字符串 rc

memcpy(ps, rc, rcsize); ps += (rcsize-1);

}

++cp;

++ps; }

*ps = '\0'; // 封闭缓冲区buf

strcpy(str , buf); delete[] buf;

return ret;}

int main()

{ char str[1024];

strcpy(str, "abcdefgabcdefgcccac");

cout << str << endl; replace_my(str, 'c', " <cccccccccccccccccccccccc> ");

cout << str << endl << endl;

return 0;}