为何我的QuickSort无法正确排序vector<string>？求调试指导

DevOps 小满

2026-8-16

问题根源与修改方案

你的快速排序代码无效的核心原因是函数参数使用了值传递而非引用传递，导致所有排序操作都只作用于原vector的副本，原数组根本没被修改。

需要修改的两个关键位置：

将Partition1函数的vector参数改为引用：

int Partition1(vector<string> &array, int low, int high)

将sort函数的vector参数改为引用：

void sort(vector<string> &array, int first, int last)

修改后的完整代码：

#include<iostream>
#include<vector>
#include<string>
using namespace std;

int Partition1(vector<string> &array, int low, int high){ //for lastName sort
    string pivot = array[high]; //pivot element
    int i = (low-1); //index of smaller element
    for(int j = low; j <= high-1; j++){ //loop from low to high
        //if current iteration is less than pivot, increment low AND swap elements at i and j
        if(array[j] < pivot){
            i++; //increment index of smaller element
            swap(array[i], array[j]);
        }
    }
    swap(array[i+1], array[high]);
    return (i+1);
}

void sort(vector<string> &array, int first, int last){
    if(first < last){
        //partition array
        int pivot = Partition1(array, first, last);
        sort(array, first, pivot-1);
        sort(array, pivot+1, last);
    }
}

void swap(string &input1, string &input2) {
    string temp; //temp student object to hold info
    temp = input1;
    input1 = input2;
    input2 = temp;
}

int main(){
    vector<string> array = {"Eric", "Bob", "George", "Fred"};
    sort(array, 0, array.size()-1);
    for(int i = 0; i < array.size(); i++){
        cout << array[i] << endl;
    }
}