如何替换char中的char*

#include <iostream>
#include <cstring>

void replaceString(char* str, const char* target, const char* replacement) {
    int targetLen = strlen(target);
    int replacementLen = strlen(replacement);
    int count = 0;

    // 计算需要替换的次数
    char* p = strstr(str, target);
    while (p) {
        count++;
        p = strstr(p + targetLen, target);
    }

    // 计算替换后的字符串长度
    int newLen = strlen(str) + count * (replacementLen - targetLen);

    // 创建新的字符数组
    char* result = new char[newLen + 1];
    char* q = result;

    // 替换字符串
    p = strstr(str, target);
    while (p) {
        int len = p - str;
        strncpy(q, str, len);
        q += len;
        strncpy(q, replacement, replacementLen);
        q += replacementLen;
        str = p + targetLen;
        p = strstr(str, target);
    }
    strcpy(q, str);

    // 输出替换后的结果
    std::cout << result << std::endl;

    // 释放内存
    delete[] result;
}

int main() {
    char str[] = "Hello, world!";
    const char* target = "world";
    const char* replacement = "everyone";

    replaceString(str, target, replacement);

    return 0;
}