24点算法课程设计实现与源代码详解

//Visual Studio 2010 亲测可用

 

#include  <iostream>  
#include  <string>  
#include  <cmath>  
 
using  namespace  std;  
 
const  double  PRECISION  =  1E-6;  
const  int  COUNT_OF_NUMBER    =  4;  
const  int  NUMBER_TO_BE_CAL  =  24;  
 
double  number[COUNT_OF_NUMBER];  
string  expression[COUNT_OF_NUMBER];  
 
bool  Search(int  n)  
{  
       if  (n  ==  1)  {  
               if  (  fabs(number[0]  -  NUMBER_TO_BE_CAL)  <  PRECISION  )  {  
                       cout  <<  expression[0]  <<  endl;  
                       return  true;  
               }  else  {  
                       return  false;  
               }  
       }  
 
       for  (int  i  =  0;  i  <  n;  i++)  {  
               for  (int  j  =  i  +  1;  j  <  n;  j++)  {  

                       double  a,  b;  
                       string  expa,  expb;  
 
                       a  =  number[i];  
                       b  =  number[j];  
                       number[j]  =  number[n  -  1];  
 
                       expa  =  expression[i];  
                       expb  =  expression[j];  
                       expression[j]  =  expression[n  -  1];  
 
                       expression[i]  =  '('  +  expa  +  '+'  +  expb  +  ')';  
                       number[i]  =  a  +  b;  
                       if  (  Search(n  -  1)  )  return  true;  
                         
                       expression[i]  =  '('  +  expa  +  '-'  +  expb  +  ')';  
                       number[i]  =  a  -  b;  
                       if  (  Search(n  -  1)  )  return  true;  
                         
                       expression[i]  =  '('  +  expb  +  '-'  +  expa  +  ')';  
                       number[i]  =  b  -  a;  
                       if  (  Search(n  -  1)  )  return  true;  
                                                 
 
                       expression[i]  =  '('  +  expa  +  '*'  +  expb  +  ')';  
                       number[i]  =  a  *  b;  
                       if  (  Search(n  -  1)  )  return  true;  
 
                       if  (b  !=  0)  {  
                               expression[i]  =  '('  +  expa  +  '/'  +  expb  +  ')';