递归连接以null结尾的字符串

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

char* concat(char* str1, char* str2) {
    int len1 = strlen(str1);
    int len2 = strlen(str2);
    char* result = (char*)malloc(len1 + len2 + 1);
    strcpy(result, str1);
    strcpy(result + len1, str2);
    result[len1 + len2] = '\0';
    return result;
}

char* recursiveConcat(char** strings, int n) {
    if (n == 0) {
        return "";
    } else if (n == 1) {
        return strings[0];
    } else {
        return concat(strings[n-1], recursiveConcat(strings, n-1));
    }
}

int main() {
    char* strings[] = {"hello", "world", "!"};
    char* result = recursiveConcat(strings, 3);
    printf("%s\n", result);
    return 0;
}