charpter7(1).txt

A
/*
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std ;
double pi = 3.14 ; 
class cirle
{
private:
    double r ; 
public:
    void get_r(double _r) {r = _r;}
    double outGet_r() {return pi*2*r;}
    double outGet_s() {return pi*r*r ; }    
}s ; 
int main()
{
    double a ; cin >> a ; 
    s.get_r(a) ;
    cout << "周长" <<s.outGet_r() << " "<< "面积" << s.outGet_s() << endl ; 
    return 0 ; 
} 
*/

B
/*
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std ;
double pi = 3.14 ; 
class sqa
{
private:
    double length , wide;
    double s ; 
public:
    void get(double _length , double _wide) 
    {
        length = _length ; 
        wide = _wide ;
        s = length * wide ; 
    }
    double outS()
    {return s;}
};
double maxn(double a , double b)
{return a > b ? a : b ; }
int main()
{
    sqa *a1, *a2 , *a3 ; 
    a1 = new sqa ; 
    a1->get(5.2 , 4.3) ; 
    a2 = new sqa ; 
    a2->get(100,20) ; 
    a3 = new sqa ; 
    double a , b ; cin >> a >> b ;
    a3->get(a,b) ; 
    cout << maxn(maxn(a1->outS() , a2->outS()),a3->outS()) << endl ; 
    return 0 ; 
}
*/

C
/*
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std ;
double pi = 3.14 ; 
class tri 
{
private:
    int a[3] ; 
private:
    bool equileteral()
    {
        if(a[0] == a[1] && a[1] == a[2]) 
            return true ; 
        else return false ; 
    }
    bool isosceles()
    {
        if(a[0] == a[1] || a[1] == a[2]) 
            return true ; 
        else return false ; 
    }
    bool right()
    {
        if(a[0] * a[0] + a[1] * a[1] == a[2] * a[2]) 
            return true ; 
        else return false ;     
    }
public:
    void get(int _a[])
    {
        for( int i = 0 ; i< 3 ; i++)
            a[i] = _a[i] ; 
    }
    void out()
    {
        if(equileteral()) {cout << "A equileteral triangle" << endl ; return ; }
        if(isosceles()) {cout << "A isosceles triangle" << endl ; return ; }
        if(right()) {cout << "A right triangle" << endl ; return ;}
        cout << "A triangle" << endl ; 
    }
} ; 
bool check(int a[])
{
    if(a[0] + a[1] <= a[2]) return false ; 
    return true ; 
}
int main()
{
    int a[3] ; 
    for( int i = 0 ; i < 3 ; i++ ) 
        cin >> a[i] ; 
    sort(a , a+3) ;
    if(!check(a)) {cout << "Not a triangle" << endl; return 0 ;} 
    tri *s ; 
    s = new tri ; 
    s->get(a) ; 
    s->out() ; 
    return 0 ; 
}
*/