import java.util.Map;
import java.util.HashMap;
import java.util.Scanner;
public class triangleTest {
 public static void main(String[] args) {
  System.out.println("==== 余弦定理 解三角形 ====");
  System.out.println();
  
  String calType = "calType";
     double num1 = 0;
  double num2 = 0;
  double num3 = 0;
  Scanner input = new Scanner(System.in);
  if(input.hasNext()){
      calType = input.next();
      num1 = input.nextDouble();
      num2 = input.nextDouble();
      num3 = input.nextDouble();
  }
  
  System.out.println("你输入了计算类型："+calType);
     
  if(calType.equals("sss")){
      System.out.println("你输入了边长a: a="+num1);
      System.out.println("你输入了边长b: b="+num2);
      System.out.println("你输入了边长c: c="+num3);
    
      Map<String,Double> triangleMap = triangleSSS(num1,num2,num3);
      
      System.out.println();
      System.out.println("====== 经计算：========");
      String A = String.format("%.2f",triangleMap.get("A"));
      String B = String.format("%.2f",triangleMap.get("B"));
      String C = String.format("%.2f",triangleMap.get("C"));
    
      System.out.println("角A为：A="+A+"度");
      System.out.println("角B为：B="+B+"度");
      System.out.println("角C为：C="+C+"度");
  }else if(calType.equals("sas")){
      System.out.println("你输入了边长b: b="+num1);
            System.out.println("你输入了边长c: c="+num2);
            System.out.println("你输入了  角A: A="+num3);
            
            Map<String,Double> triangleMap = triangleSAS(num1,num2,num3);
            
            System.out.println();
            System.out.println("====== 经计算：========");
            System.out.println("第三边a长度为：a="+triangleMap.get("a"));
            System.out.println("角B为：B="+triangleMap.get("B"));
            System.out.println("角C为：C="+triangleMap.get("C"));
  }else{
       System.out.println("请正确输入你想要计算的类型：sss 或 sas ");
  }
 }
 
    public static Map<String,Double> triangleSAS(double b,double c, double A){
      
      Map<String,Double> triangleMap = new HashMap<String,Double>();
      double radiansA = Math.toRadians(A);
      double a = Math.sqrt(b*b+c*c - 2*b*c*Math.cos(radiansA));
      triangleMap.put("a",a);
     
      double fenzi = c*c + a*a - b*b;
      double fenmu = 2*c*a;
      double cosB = fenzi / fenmu;
      double B = Math.toDegrees(Math.acos(cosB));
      triangleMap.put("B",B);
      triangleMap.put("C",180-B-A);
      
      return triangleMap;
    }
      
 public static Map<String,Double> triangleSSS(double a,double b,double c){
     
     Map<String,Double> triangleMap = new HashMap<String,Double>();
    
     double fenziA = c*c + b*b - a*a;
     double fenmuA = 2*b*c;
     double cosA = fenziA / fenmuA;
     double A = Math.toDegrees(Math.acos(cosA));
     
     double fenziB = c*c + a*a - b*b;
     double fenmuB = 2*c*a;
     double cosB = fenziB / fenmuB;
     double B = Math.toDegrees(Math.acos(cosB));
     
     double fenziC = a*a + b*b - c*c;
     double fenmuC = 2*a*b;
     double cosC = fenziC / fenmuC;
     double C = Math.toDegrees(Math.acos(cosC));
     triangleMap.put("A",A);
     triangleMap.put("B",B);
     triangleMap.put("C",C);
     return triangleMap;
 }
}