8_3.cpp

来自「本文档是（作者：钱能）《C＋＋程序设计教程》课后习题答案。 选题编辑：张朝阳 」· C++ 代码 · 共 84 行

//8_3

#include <iostream.h>
#include <stdlib.h>

int CompIntBitSum(const void* a, const void* b);
int CompFloat(const void* a, const void* b);
int CompStrLen(const void* a, const void* b);

void main()
{
  int a[]={12,32,42,51,8,16,21,19,9};
  int anum=sizeof(a)/sizeof(*a);
  cout <<"\n排序前:\n";
  for(int i=0; i<anum; i++)
    cout <<a[i] <<" ";
  cout <<endl;

  qsort(a,anum,sizeof(*a), CompIntBitSum);

  cout <<"排序后:\n";
  for(int i=0; i<anum; i++)
    cout <<a[i] <<" ";
  cout <<endl;

  float f[]={32.1,456.87,332.67,442.0,98.12,
             451.79,340.12,54.55,99.87,72.5};
  int fnum=sizeof(f)/sizeof(*f);
  cout <<"\n排序前:\n";
  for(int i=0; i<fnum; i++)
    cout <<f[i] <<" ";
  cout <<endl;

  qsort(f,fnum,sizeof(*f), CompFloat);

  cout <<"排序后:\n";
  for(int i=0; i<fnum; i++)
    cout <<f[i] <<" ";
  cout <<endl;

  char* str[]={"enter","number","size","begin","of","cat",
               "case","program","certain","a"};
  int strnum=sizeof(str)/sizeof(*str);
  cout <<"\n排序前:\n";
  for(int i=0; i<strnum; i++)
    cout <<str[i] <<" ";
  cout <<endl;

  qsort(str,strnum,sizeof(*str), CompStrLen);

  cout <<"排序后:\n";
  for(int i=0; i<strnum; i++)
    cout <<str[i] <<" ";
  cout <<endl;
}

int CompIntBitSum(const void* a, const void* b)
{
  int ia=*(int*)a, ib=*(int*)b;
  int suma=0,sumb=0;
  while(ia){
    suma+=ia%10;
    ia/=10;
  }
  while(ib){
    sumb+=ib%10;
    ib/=10;
  }
  return suma - sumb;
}

int CompFloat(const void* a, const void* b)
{
  return *(float*)a - *(float*)b;
}

int CompStrLen(const void* a, const void* b)
{
  if(strlen(*(char**)a)==strlen(*(char**)b))
    return strcmp(*(char**)a, *(char**)b);
  return strlen(*(char**)a) - strlen(*(char**)b);
}