一些算法

#include <iostream>
#include <cstring>
using namespace std;
void shellsort(int v[],int n)
{
    int gap,i,j,temp;
    for (gap = n/2 ; gap >0 ; gap /= 2)
    {
        for (i = gap; i < n ; ++i)
        {
            for (j = i - gap ; j >=0 && v[j] > v[j+gap] ; j -= gap)
            {
                temp = v[j];
                v[j] = v[j + gap];
                v[j+gap] = temp;
            }
        }
    }
}
//倒置字符串s中各个字符的位置
void reverse(char s[])
{
    int ch;
    for (int i = 0,j = strlen(s) - 1;i < j ; i++,j-- )
    {
        ch = s[i];
        s[i] = s[j];
        s[j] = ch;
    }
}
//将整数n转换为字符串并保存在s中
void itoa(int n ,char s[])
{
    int i ,sign;
    if ((sign = n) < 0 )
    {
        n = -n;
    }
    i = 0;
    do 
    {
        s[i++] = n%10 +'0';
    } while (( n = n/10) > 0 );
    if (sign < 0 )
    {
        s[i++] = '-';
    }
    s[i] = '';
    reverse(s);
}

//将n格式化为以b为底的数，保存在s中
void itob(int n,char s[] ,int b)
{
    int i ,sign;
    if ((sign = n) < 0 )
    {
        n = -n;
    }
    i = 0;
    do 
    {
        s[i++] = n%b + '0';
    } while ((n = n / b) >0);

    if (sign < 0)
    {
        s[i++] = '-';
    }

    s[i] = '';
    reverse(s);
}

//删除字符串尾部的空格、制表符、换行符
void trim(char s[])
{
    for (int i = strlen(s) - 1 ; i >0 ; i --)
    {
        if (s[i] != ' ' && s[i] != '	' && s[i] != '
')
        {
            break;
        }
    }
    s[i+1] = '';
}

void main()
{
    char s[10];
    itob(8,s,17);
    cout<<s<<endl;
}