import?java.util.Scanner;
public?class?Triangle
{
/**
?*?等腰
?*/
public?static?final?int?ISOSCELES?=?1;
/**
?*?等邊
?*/
public?static?final?int?EQUILATERAL?=?2;
/**
?*?直角
?*/
public?static?final?int?RIGHTANGLE?=?4;
/**
?*?普通
?*/
public?static?final?int?GENERAL?=?6;
/**
?*?不構成三角形
?*/
public?static?final?int?NOTHING?=?7;
double?a;
double?b;
double?c;
public?Triangle?(?double?a,?double?b,?double?c?)
{
this.a?=?a;
this.b?=?b;
this.c?=?c;
}
public?static?int?isWhichOne?(?Triangle?triangle?)
{
double?a?=?triangle.a;
double?b?=?triangle.b;
double?c?=?triangle.c;
if?(a?+?b?>?c?&&?a?+?c?>?b?&&?b?+?c?>?a?&&?Math.abs?(a?-?b)?<?c?&&?Math.abs?(a?-?c)?<?b?&&?Math.abs?(b?-?c)?<?a)
{
if?(a?==?b?&&?a?==?c)
{
return?Triangle.EQUILATERAL?|?Triangle.ISOSCELES;
}
else?if?(a?*?a?+?b?*?b?==?c?*?c?||?a?*?a?+?c?*?c?==?b?*?b?||?c?*?c?+?b?*?b?==?a?*?a)
{
if?(a?==?b?||?a?==?c?||?b?==?c)
{
return?Triangle.RIGHTANGLE?|?Triangle.ISOSCELES;
}
return?Triangle.RIGHTANGLE;
}
else?if?(a?==?b?||?a?==?c?||?b?==?c)
{
return?Triangle.ISOSCELES;
}
else
{
return?Triangle.GENERAL;
}
}
else
{
return?Triangle.NOTHING;
}
}
public?static?double?perimeter?(?Triangle?triangle?)
{
return?triangle.a?+?triangle.b?+?triangle.c;
}
public?static?double?area?(?Triangle?triangle?)
{
double?a?=?triangle.a;
double?b?=?triangle.b;
double?c?=?triangle.c;
return?1.d?/?4?*?Math.sqrt?((?a?+?b?+?c?)?*?(?a?+?b?-?c?)?*?(?a?+?c?-?b?)?*?(?b?+?c?-?a?));
}
public?static?void?translate?(?Triangle?triangle?)
{
int?type?=?isWhichOne?(triangle);
switch?(type)
{
case?Triangle.ISOSCELES:
System.out.println?("等腰三角形");
break;
case?(?Triangle.EQUILATERAL?|?Triangle.ISOSCELES?):
System.out.println?("等邊三角形?+?等腰三角形");
break;
case?Triangle.GENERAL:
System.out.println?("普通三角形");
break;
case?(?Triangle.RIGHTANGLE?|?Triangle.ISOSCELES?):
System.out.println?("直角三角形?+?等腰三角形");
break;
case?Triangle.RIGHTANGLE:
System.out.println?("直角三角形");
break;
default:
System.out.println?("不構成三角形");
break;
}
if?(type?!=?Triangle.NOTHING)
{
System.out.println?("周長是："?+?perimeter?(triangle));
System.out.println?("面積是："?+?area?(triangle));
}
}
public?static?void?main?(?String[]?args?)
{
System.out.println?("輸入構成三角形的三邊長：(空格隔開)\n退出按?(n/N),?否則繼續:?");
String?error?=?"輸入有誤，請重新輸入:?";
String?reg?=?"^\\d+\\s+\\d+\\s+\\d+$";
Scanner?scanner?=?new?Scanner?(System.in);
while?(scanner.hasNextLine?())
{
String?line?=?scanner.nextLine?().trim?();
if?("n".equalsIgnoreCase?(line))
{
break;
}
if?(!line.matches?(reg))
{
System.err.println?(error);
}
else
{
try
{
String[]?input?=?line.split?("\\s+");
int?a?=?Integer.parseInt?(input[0]);
int?b?=?Integer.parseInt?(input[1]);
int?c?=?Integer.parseInt?(input[2]);
Triangle?triangle?=?new?Triangle?(a,?b,?c);
translate?(triangle);
}
catch?(NumberFormatException?e)
{
System.err.println?(error);
}
System.out.println?("退出按?(n/N),?否則繼續:?");
}
}
scanner.close?();
}
}