Question

当我尝试编译以下代码时，我一直都会遇到错误，我目前正在使用JCreator。

import java.io.*;

public class Number //class name here, same as file name

 {
 public Number()throws IOException{//constructor, place class name here
 // use BufferedReader class to input from the keyboard
 // declare a variable of type BufferedReader
 BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
 //declare variable for input
 String inputString;

int number;
int counter;
int square;
int cube;
String goodMessage = "Thank you";
String badMessage = "Sorry";

//begin houseKeeping()
System.out.print("Please input number: ");
inputString = input.readLine();
number = Integer.parseInt(inputString);

//begin squareCube()
counter = 0;
while ((counter = 0)&&(number > 0)) {
    square = number*number;
    cube = number*number*number;
    System.out.print(square);
    System.out.print(cube);
}
if (counter = counter + 1);
if (counter < 3);
System.out.print("Enter input number: ");

//begin finishUp()
if (number > 0)
    System.out.println(goodMessage);

    else 
    System.out.println(badMessage);

 }//end constructor

 public static void main(String [] args) throws IOException // main method

 {
 new Number(); //class constructor name
 } // end the main method
 } // end the program

错误：

--------------------Configuration: <Default>--------------------
D:\INFO\INFO 1391\Number.java:27: error: bad operand types for binary operator '&&'
    while ((counter = 0)&&(number > 0)) {
                        ^
  first type:  int
  second type: boolean
1 error

Process completed.

Answer 1

您无法使用=运算符来比较值;这是赋值运算符。使用==来比较int值：

while ((counter == 0)&&(number > 0)) {

此处的赋值运算符求值为int，产生您收到的错误消息。

Answer 2

counter = 0

应该是

counter == 0

Answer 3

while ((counter = 0)&&(number > 0))永远不会成立，因为(counter = 0)会将计数器指定为0，而该语句的值是counter：0的值。 0为int，无法转换为boolean。

Answer 4

问题在哪里？

此代码中有很多错误...... 要检查两个整数是否相等，您必须写== not =。（在while和in中）。

while-loop语句有问题

4 个答案: