c++24点源代码.txt

c++24点（源码）,好用

＃i nclude <iostream> 
＃i nclude <string> 
＃i nclude <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 + ')'; 
number[i] = a / b; 
if ( Search(n - 1) ) return true; 
} 
if (a != 0) { 
expression[i] = '(' + expb + '/' + expa + ')'; 
number[i] = b / a; 
if ( Search(n - 1) ) return true; 
} 

number[i] = a; 
number[j] = b; 
expression[i] = expa; 
expression[j] = expb; 
} 
} 
return false; 
} 

void main() 
{ 
for (int i = 0; i < COUNT_OF_NUMBER; i++) { 
char buffer[20]; 
int x; 
cin >> x; 
number[i] = x; 
itoa(x, buffer, 10); 
expression[i] = buffer; 
} 

if ( Search(COUNT_OF_NUMBER) ) { 
cout << "Success." << endl; 
} else { 
cout << "Fail." << endl; 
} 
}