c++ - 用 C++ 对数字进行排序

Question

因此，我编写了对数字进行排序的程序，但每当我执行它时，它都会将最小的随机数添加为“已排序数字”行中的第一个。

代码如下:

#include "stdafx.h"
#include <stdlib.h>
#include <iostream>
#include <time.h>

using namespace std;

int main(){

    const int MAX_SIZE = 100;
    int numbers[MAX_SIZE];
    int numElements;

    cout << "=============================" << endl;
    cout << "Welcome to BubbleSort Program" << endl;
    cout << "=============================" << endl;
    cout << endl;

    cout << "How many random numbers do you want us to produce? ";
    cin >> numElements;
    cout << endl;


    srand(static_cast<unsigned int>(time(0)));

    cout << "=============================" << endl;
    cout << "Random numbers: " << endl;
    cout << "=============================" << endl;

    for(int i = 0; i < numElements; i++){

        numbers[i] = (rand()%100) + 1;
        cout << numbers[i] << endl;
        if(i == numElements){
            cout << "i";
        }
    }


    int exchanges;
    int temp;
    int j;

    cout << "=============================" << endl; 
    cout << "Sorted numbers: " << endl;
    cout << "=============================" << endl;

    for(int i = 0; i <= numElements; i++){
        for(int j = 0; j < numElements; j++){

            if(numbers[j] > numbers[j + 1]){

                temp = numbers[j];
                numbers[j] = numbers[j + 1];
                numbers[j + 1] = temp;

            }
        }
    }

    for(int i = 0; i <= numElements; i++) {
        cout << numbers[i] << endl;
    }

    cout << "=============================" << endl;
    return 0;
}

输出示例:

============================= Welcome to BubbleSort Program =============================

How many random numbers do you want us to produce? 3

=============================
Random numbers:
=============================
69
8
5
=============================
Sorted numbers:
=============================
-858993460
5
8
69
=============================
Press any key to continue . . .

WTF 是-858993460？!

Answer 1

您正在访问未初始化的内存 -

for(int i = 0; i <= numElements; i++) { // <-- no, stop at < -- see above.
  for(int j = 0; j < numElements; j++) // <-- you use j+1 below

应该是

for (int i = 0; i < numElements; i++) { // <-- also not initialized.
  for (int j = 0; j < numElements - 1; j++) // <-- like so.