c语言编写一个函数char*sbstr（char*p ）

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

char* sbstr(char* p, char* t1, char* t2) {
    char* last_occurrence = strrchr(p, t1[0]); // 找到t1最后一次出现的位置
    if (last_occurrence != NULL) {
        int t1_len = strlen(t1);
        int t2_len = strlen(t2);
        int p_len = strlen(p);
        int new_len = p_len - t1_len + t2_len; // 新串的长度
        char* new_str = malloc(new_len + 1); // 分配新串的内存空间
        strncpy(new_str, p, last_occurrence - p); // 复制t1之前的部分到新串中
        strcpy(new_str + (last_occurrence - p), t2); // 复制t2到新串中
        strcpy(new_str + (last_occurrence - p) + t2_len, last_occurrence + t1_len); // 复制t1之后的部分到新串中
        return new_str;
    }
    return p;
}

int main() {
    char s[100];
    char t1[100];
    char t2[100];
    char w[100];

    printf("请输入s所指字符串：");
    scanf("%s", s);
    printf("请输入t1所指字符串：");
    scanf("%s", t1);
    printf("请输入t2所指字符串：");
    scanf("%s", t2);

    char* result = sbstr(s, t1, t2);
    strcpy(w, result);
    printf("替换后的新串：%s\n", w);

    return 0;
}