c语言现在有一个字符串我怎么实现指定另外一个字符串和是否大小写敏感的参数进行对该字符串替换的一个函数有几种方式每种方式给出具体完整可以运行的代码

以下是两种实现方式：

方式一：使用标准库函数strtok、strcmp和strcpy实现字符串替换

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

void replace_str(char *str, const char *old_str, const char *new_str, int case_sensitive) {
    char *token, *str_ptr, *new_str_ptr, *temp_str;
    int old_len = strlen(old_str), new_len = strlen(new_str);
    temp_str = (char *)malloc(strlen(str) + 1);
    strcpy(temp_str, str);
    str_ptr = temp_str;

    while ((token = strtok(str_ptr, old_str)) != NULL) {
        str_ptr = NULL;
        if (case_sensitive ? strcmp(token, old_str) == 0 : strcasecmp(token, old_str) == 0) {
            new_str_ptr = (char *)malloc(strlen(token) + new_len + 1);
            strcpy(new_str_ptr, new_str);
            strcat(new_str_ptr, token + old_len);
            strcpy(token, new_str_ptr);
            free(new_str_ptr);
        }
    }
    strcpy(str, temp_str);
    free(temp_str);
}

int main() {
    char str[] = "Hello, World! This is a test string.";
    replace_str(str, "test", "example", 1);
    printf("%s\n", str);
    replace_str(str, "hello", "Hi", 0);
    printf("%s\n", str);
    return 0;
}

方式二：使用指针操作实现字符串替换

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

void replace_str(char *str, const char *old_str, const char *new_str, int case_sensitive) {
    char *str_ptr = str, *old_ptr, *new_ptr;
    int old_len = strlen(old_str), new_len = strlen(new_str);

    while (*str_ptr != '\0') {
        old_ptr = (char *)old_str;
        new_ptr = (char *)new_str;
        while (*str_ptr != '\0' && (case_sensitive ? *str_ptr == *old_ptr : tolower(*str_ptr) == tolower(*old_ptr))) {
            str_ptr++;
            old_ptr++;
        }
        if (*old_ptr == '\0') {
            char *temp_ptr = str_ptr - old_len;
            char *temp_str = (char *)malloc(strlen(str_ptr) + 1);
            strcpy(temp_str, str_ptr);
            *temp_ptr = '\0';
            strcat(str, new_str);
            strcat(str, temp_str + old_len);
            free(temp_str);
            str_ptr = temp_ptr + new_len;
        } else {
            str_ptr++;
        }
    }
}

int main() {
    char str[] = "Hello, World! This is a test string.";
    replace_str(str, "test", "example", 1);
    printf("%s\n", str);
    replace_str(str, "hello", "Hi", 0);
    printf("%s\n", str);
    return 0;
}
``