C++11写算法之选择排序

选择排序，顾名思义，指从数组后面将最小的值找出来，然后与最前面（指当前位置）值进行交换。

时间复杂度：O(n^2)

空间复杂度：O(1)

此处应用了C++11的auto , lambda , static_assert 。

show me the code ！

// #if __cplusplus < 201103L 
// #error "must be compiled under c++11 support platform!!!"
// #endif
#include <iostream>
#include <algorithm>
#include <iterator>
#include <cassert>
using namespace std;

void Swap(int& a, int& b)
{
    int tmp = a;
    a = b;
    b = tmp;
}
void SelectSort(int varList[], const int size)
{
    if (!varList || size <= 1)
    {
        return;
    }
    for (int i = 0; i < size; i++)
    {
        int swapPos = i;
        for (int j = i; j < size; j++)
        {
            if (varList[swapPos] > varList[j])
            {
                swapPos = j;
            }
        }
        if (i != swapPos)
        {
            Swap(varList[i], varList[swapPos]);
        }
    }
}

void test()
{
    //case counter
    int testCase = 0;
    //sort function object
    auto sortFunc = SelectSort;
    //show case result lambda function
    auto showFunc = [&testCase](const char* caseDescription){cout << "case[" << testCase++ << "]	(" << caseDescription << ") 		ok " << endl; };

    cout << "test begin : " << endl << endl;

    //case empty list
    {
        sortFunc(nullptr, 0);
        showFunc("case empty list");
    }
    //case wrong size
    {
        int nTestList[] = { 13, 52, 32, 15, 66, 2, 99, 202, 103, 2 };
        sortFunc(nTestList, 0);
        showFunc("case wrong size");
    }
    //case size == 1
    {
        int var = 13;
        int varList[] = { var };
        sortFunc(varList, 1);
        assert(var == varList[0]);
        showFunc("case size == 1");
    }
    //case normal sort
    {
        int varList[] = { 13, 52, 32, 15, 66, 2, 99, 202, 103, 2 };
        const int size = sizeof(varList) / sizeof(int);
        const int resultList[] = { 2, 2, 13, 15, 32, 52, 66, 99, 103, 202 };
        static_assert(sizeof(varList) == sizeof(resultList), "size of varList is not equal with resultList!!");

        sortFunc(varList, size);
        for (int i = 0; i < size; i++){ assert(varList[i] == resultList[i]); }
        showFunc("case normal sort");
    }
    //case sorted list
    {
        int varList[] = { 2, 2, 13, 15, 32, 52, 66, 99, 103, 202 };
        const int size = sizeof(varList) / sizeof(int);
        const int resultList[] = { 2, 2, 13, 15, 32, 52, 66, 99, 103, 202 };
        static_assert(sizeof(varList) == sizeof(resultList), "size of varList is not equal with resultList!!");

        sortFunc(varList, size);
        for (int i = 0; i < size; i++){ assert(varList[i] == resultList[i]); }
        showFunc("case sorted list");
    }
    cout << endl << "test done ! " << endl << endl;
}
int main(int argc, char* argv[])
{
    test();
    return 0;
}