用C++写一个数字 n 代表生成括号的对数，用于能够生成所有可能的并且 有效的 括号组合的程序

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

void generateParenthesis(int n, char** result, int* returnSize) {
    if (n <= 0) {
        return;
    }
    char* str = (char*)malloc(sizeof(char) * (2 * n + 1));
    memset(str, 0, sizeof(char) * (2 * n + 1));
    int left = n, right = n;
    int pos = 0;
    generate(str, left, right, pos, result, returnSize);
    free(str);
}

void generate(char* str, int left, int right, int pos, char** result, int* returnSize) {
    if (left == 0 && right == 0) {
        result[*returnSize] = (char*)malloc(sizeof(char) * (strlen(str) + 1));
        strcpy(result[*returnSize], str);
        (*returnSize)++;
        return;
    }
    if (left > 0) {
        str[pos] = '(';
        generate(str, left - 1, right, pos + 1, result, returnSize);
    }
    if (right > left) {
        str[pos] = ')';
        generate(str, left, right - 1, pos + 1, result, returnSize);
    }
}

int main() {
    int n = 3;
    int returnSize = 0;
    char** result = (char**)malloc(sizeof(char*) * 1000);
    generateParenthesis(n, result, &returnSize);
    printf("All valid combinations of %d pairs of parentheses:\n", n);
    for (int i = 0; i < returnSize; i++) {
        printf("%s\n", result[i]);
        free(result[i]);
    }
    free(result);
    return 0;
}