基数排序

/*具体原理：从低位到高位对输入数据个位数字一次进行计数排序*/

#include "stdafx.h"
#include<iostream>
using namespace std;

int Location_num(int in,int location){//求一个数的第location位数字
 int temp = 1;
 for(int i = 0;i < location-1;++i)temp *= 10;
 return (int)((in%(10*temp))/temp);
}

void Count_sort(int *out,int *in,int location,int length){//依据第locaton位数字进行计数排序
 int a[10];
 for(int i = 0;i < 10;++i){
  a[i] = 0;
 }
 for(int i = 0;i < length;++i){

  ++a[Location_num(in[i],location)];
 }
 for(int i = 0;i < 9;++i){
  a[i+1] += a[i];
 }
 for(int i = length-1;i > -1;--i){
     out[--a[Location_num(in[i],location]] = in[i];
   }
}

int *Radix_sort(int *in,int length,int maxwidth){//基数排序实现
 int *Out = new int[length];
 for(int i = 2;i <= maxwidth;++i){
  Count_sort(Out,in,i,length);
  for(int j = 0;j <= length-1;++j){//按照从低位到高位分别进行一次计数排序
   in[j] = Out[j];
  }
 }
 delete[] Out;
 return in;
}

void main(){

 /*基数排序测试数据*/
 int p[] = {

123,456,789,456,

654,987,321,369,

258,147,741,852,

966,48,5,54,6,56,

45654,6,54,9,54,

665,665,5454,45,

54,54,6,45654,32,

132,213,123,123,

465,654,654,564,

654,56,4654,465,

456465,458

};
 int length = sizeof(p)/sizeof(int);
 Radix_sort(p,length,6);
 for(int i = 0;i < length;++i)cout<<p[i]<<" ";//显示排序结果
 cout<<endl<<endl;

}