PracticeDev/study_cpp/sort/sort_test_3.cpp

// sort algorithm example
#include <iostream>     // std::cout
#include <algorithm>    // std::sort
#include <vector>       // std::vector
#include <cstring>      // memcpy

bool myfunction (int i,int j) { return (i<j); }//升序排列
bool myfunction2 (int i,int j) { return (i>j); }//降序排列

struct myclass {
  bool operator() (int i,int j) { return (i>j);}
} myobject;

void printfVector(std::vector<int> myvector)
{
  for (std::vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)//输出
    std::cout << ' ' << *it;
  std::cout << '\n';
}

int main () {
  int myints[8] = {32,71,12,45,26,80,53,33};
  int sort[8];
  std::vector<int> myvector (myints, myints+8);               // 32 71 12 45 26 80 53 33
  memcpy(sort, myints, sizeof(myints));
  std::vector<int> vector_sort (sort, sort+8);

  std::cout << "测试数组:";
  printfVector(myvector);

  memcpy(sort, myints, sizeof(myints));
  std::cout << "默认排序前四个元素(<):";
  printfVector(myvector);
  std::sort (vector_sort.begin(), vector_sort.begin()+4);           //(12 32 45 71)26 80 53 33
  std::cout << "排序结果:";
  printfVector(myvector);

  memcpy(sort, myints, sizeof(myints));
  std::cout << "默认排序后四个元素(<):";
  printfVector(myvector);
  std::sort (vector_sort.begin()+4, vector_sort.end());
  std::cout << "排序结果:";
  printfVector(myvector);

   // using default comparison (operator <):
  memcpy(sort, myints, sizeof(myints));
  std::cout << "默认比较(<):";
  printfVector(myvector);
  std::sort (vector_sort.begin(), vector_sort.end());
  std::cout << "排序结果:";
  printfVector(myvector);

  // using function as comp
  memcpy(sort, myints, sizeof(myints));
  std::cout << "用fuction进行比较排序 (<):";
  printfVector(myvector);
  std::sort (vector_sort.begin(), vector_sort.end(), myfunction); // 12 32 45 71(26 33 53 80)
    //std::sort (myints,myints+8,myfunction);不用vector的用法
  std::cout << "排序结果:";
  printfVector(myvector);

  // using function2 as comp
  memcpy(sort, myints, sizeof(myints));
  std::cout << "用fuction2进行比较排序 (>):";
  printfVector(myvector);
  std::sort (vector_sort.begin(), vector_sort.end(), myfunction2);
    //std::sort (myints,myints+8,myfunction);不用vector的用法
  std::cout << "排序结果:";
  printfVector(myvector);

  // using object as comp
  memcpy(sort, myints, sizeof(myints));
  std::cout << "用object进行比较排序 (>):";
  printfVector(myvector);
  std::sort (vector_sort.begin(), vector_sort.end(), myobject);     //(12 26 32 33 45 53 71 80)
  // print out content:
  std::cout << "排序结果:";
  printfVector(myvector);

  std::cout << "不用vector的用法:";
  printfVector(myvector);
  memcpy(sort, myints, sizeof(myints));
  // std::sort (myvector.begin(), myvector.end(), myfunction);
  std::sort (myints,myints+8,myfunction); //不用vector的用法
  std::cout << "排序结果:";
  // printfVector(myvector);
  for(int i=0;i<9;i++)
  {
    std::cout << ' ' << myints[i];
  }
  std::cout << '\n';

  return 0;
}