C++ 冒泡排序與sort函數

步驟和原理，上兩張圖：

代碼實現：

#include<iostream>
using namespace std;

int main()
{
	int arr[] = { 1, 3, 5, 7, 9, 2, 4, 8, 6, 10 };
	int arrLength = sizeof(arr) / sizeof(arr[0]);
	cout << "排序前：";
	for (int i = 0; i < arrLength; i++)
		cout << arr[i]<<" ";
	for (int i = 0; i < arrLength-1; i++) //排序總輪數 = 元素個數 - 1
	{
		for (int j = 0; j < arrLength - i - 1; j++) //每輪對比次數 = 元素個數 - 排序總輪數 - 1
		{
			if(arr[j] > arr[j + 1])
			{
				int temp = arr[j + 1];
				arr[j + 1] = arr[j];
				arr[j] = temp;
			}
		}
	}
	cout << "\n排序後：";
	for (int i = 0; i < arrLength; i++)
		cout << arr[i] << " ";
	cout << endl;
	return 0;
}

運行結果： 

 

當然C++ sort函數可以快速實現從小到大或從大到小排列數組：

#include<iostream>
#include<algorithm>
using namespace std;

bool compare(int a, int b);

int main()
{
	int arr[] = { 1, 3, 5, 7, 9, 2, 4, 8, 6, 10 };
	int arrLength = sizeof(arr) / sizeof(arr[0]);
	cout << "排序前：";
	for (int i = 0; i < arrLength; i++)
		cout << arr[i] << " ";
	//sort(arr, arr + arrLength); //默認從小到大順序排列
	sort(arr, arr + arrLength, compare); //指定從大到小順序排列
	cout << "\n排序後：";
	for (int i = 0; i < arrLength; i++)
		cout << arr[i] << " ";
	cout << endl;
}

//自定義函數
bool compare(int a, int b)
{
	return a > b;
}