我的代码没有编译，因为“缺少返回语句”错误，但我不明白为什么？[复制]

Question

   public static String triangleCheck(){ // Triangle Method
      Scanner scan = new Scanner(System.in);
      
            System.out.print("What is the length of side 1? ");
            int side1 = scan.nextInt();
            System.out.print("what is the length of side 2? ");
            int side2 = scan.nextInt();
            System.out.print("What is the length of side 3? ");
            int side3 = scan.nextInt();

      if (!(side1+side2>side3 && side2+side3>side1 && side3+side1>side2))
         return " However your measure don't quite make a full triangle. ";
         
      else if ((side1 > side2) && (side1 > side3))
         if(side1*side1 == side2*side2 + side3*side3)
            return "It is a right triangle.";
         else if((side1*side1) > side2*side2 + side3*side3)
            return "It is an obtuse triangle.";
         else 
            return "It is an acute triangle.";
            
      else if ((side2 > side1) && (side2 > side3))
         if(side2*side2 == side1*side1 + side3*side3)
            return "It is a right triangle.";
            else if((side2*side2) > side1*side1 + side3*side3)
               return "It is an obtuse triangle.";
         else 
            return "It is an acute triangle.";
      
      else if ((side3 > side1) && (side3 > side2))
            if (side2*side2 == side1*side1 + side3*side3)
               return "It is a right triangle.";
            else if((side2*side2) > side1*side1 + side3*side3)
               return "It is an obtuse triangle.";
            else 
               return "It is an acute triangle.";
}

这是我的程序的方法我正在尝试运行我的代码，但它不会运行它说错误：缺少返回语句“}”，我认为这个if/else部分是问题所在，但我无法找出我哪里做错了，以及如何修复它

Answer 1

在所有if/else条件结束时，添加最后一个else来处理无效输入。

...
else {
    return "Error: Unable to check triangle.";
}