#include

本文是后续文章中涉及到的基本函数源代码。

001、生成随机数

unsigned int latestRandNum = 1;

/*设置随机数种子*/
void srandGLibC(unsigned int seed)
{
    latestRandNum = (seed == 0 ? 1 : seed);
}

/*生成[0, 2147483647]之间的随机数*/
int randGLibC(void)
{
    int randNum = ((latestRandNum * 1103515245) + 12345) & 0x7fffffff;
    latestRandNum = randNum;
    
    return (latestRandNum); 
}

/*在指定范围内生成随机数*/
int randRange(int min, int max)
{
    unsigned int range = max - min + 1;

    if (range == 1 || range > 2147483648)
    {
        return min;
    }
    else if (range < 1)
    {
        throw std::range_error("The upper limit is less than the lower limit!");
        return -1;
    }

    return (randGLibC() % range + min);
}

002、生成元素为[min, max]之间随机数的整型数组

/*生成元素为[min, max]之间随机数的整型数组*/
void randArray(int a[], int len, int min, int max)
{
    //srandGLibC(static_cast<unsigned int>(time(NULL)) + rand());
    for (int i = 0; i != len; ++i)
    {
        a[i] = randRange(min, max);
    }
}

003、复制数组

/*复制数组*/
void copyArray(int src[], int src_beg, int dest[], int dest_beg, int len)
{
    for (int i = 0; i != len; ++i)
    {
        dest[dest_beg + i] = src[src_beg + i];
    }
}

004、交换数组元素

/*交换数组元素*/
void swap(int a[], int loca, int locb)
{
    if (loca != locb)
    {
        int temp = a[loca];
        a[loca] = a[locb];
        a[locb] = temp;
    }
}

005、快速排序

/*快排一趟划分*/
int partition(int a[], int beg, int end)
{
    int pivot = a[end];
    int i = beg - 1;

    for (int j = beg; j != end; ++j)
    {
        if (a[j] <= pivot)
        {
            swap(a, ++i, j);
        }
    }
    swap(a, i + 1, end);

    return i + 1;
}

/*快速排序*/
void quickSort(int a[], int beg, int end)
{
    if (beg < end)
    {
        int mid = partition(a, beg, end);
        quickSort(a, beg, mid - 1);
        quickSort(a, mid + 1, end);
    }
}

1 /*交换数组元素*/
2 void swap(int a[], int loca, int locb)
3 {
4     int temp = a[loca];
5     a[loca] = a[locb];
6     a[locb] = temp;
7 }

 1 /*指定枢轴节点的划分*/
 2 int partition_specify_pivot(int a[], int beg, int end, int pivotloc)
 3 {
 4     int pivot = a[pivotloc];
 5     int i = beg - 1;
 6     int e = end;
 7 
 8     swap(a, pivotloc, e);
 9     for (int j = beg; j != e; ++j)
10     {
11         if (a[j] <= pivot)
12         {
13             ++i;
14             swap(a, i, j);
15         }
16     }
17     swap(a, i + 1, e);
18 
19     return i + 1;
20 }

006、直接插入排序

/*直接插入排序*/
void insertionSort(int a[], int beg, int end)
{
    for (int j = beg + 1; j <= end; ++j)
    {
        int key = a[j];
        int i = j - 1;
        while ((i >= beg) && (a[i] > key))
        {
            a[i + 1] = a[i];
            --i;
        }
        a[i + 1] = key;
    }
}

007、输出数组元素

/*输出数组元素*/
void outputArray(std::ostream& os, int a[], int beg, int end, int step, int width)
{
    int len = end - beg + 1;
    //下标所需的位数
    int iterWidth = static_cast<int>(log(static_cast<double>(len - 1)) / log(10.0)) + 1;

    os << "The content of the array is:" << std::endl;
    if (len > 0)
    {
        os  << "array[" << std::setfill('0') << std::setw(iterWidth) << beg 
            << "] = " << std::setfill(' ') << std::setw(width) << a[beg] 
            << std::endl;
    }
    for (int i = beg + step; i <= end; i += step)
    {
        os << "array[" << std::setfill('0') << std::setw(iterWidth) << i << "] = " 
           << std::setfill(' ') << std::setw(width) << a[i] << std::endl;
    }
}