为什么我的程序无法识别输入“ q”并中断循环？

Question

I'm writing a main method that asks the user for input in the form of the length of the radius and height of a cone, and then calls 3 other mathematical methods to determine the area of the bottom of the cone, as well as the surface area and volume of it.

The idea is that you should be able to enter several sets of inputs, and signal that you're done by entering "q". An example input could for example be " 10 5 6 8 q". The program should then calculate everything two times, with two sets of radius and height and then break the loop. Instead, it does the calculations 3 times, where the last two are identical. Also it doesn't jump to the next piece of code after the infinite loop.

outerLoop: while(true)       //Infinite loop
{   
if (scan.hasNextInt())       //If next input is an integer, read it
{
radie = scan.nextInt();
height = scan.nextInt();
}
else if (scan.next().equals('q'))
{                          //If it instead if "q", break the loop  
    break outerLoop;
}
     System.out.print("r = "+radius);
     System.out.println("h = "+height);
     System.out.println("Bottom area:      "+ area(radius));
     System.out.println("Surface area:   "+area(radie, height));
     System.out.println("Volume:              "+ volume(radius, height));

}

}

Answer 1

您正在将一个字符串（scan.next（））与一个字符'q'比较，该字符将永远不相等。

Answer 2

else if (scan.next().equals("q"))
{                          
    break outerLoop;
}

You are comparing a String vs a Char. Try with this and it will work.