二维数组

Question

I am having troubles with my "for" loop in my program. The main error I am getting is "type mismatch: cannot convert from int to Boolean." All I want to do is to have the corresponding "time" element printed out. I know that conditions need to be of type bool for "classNames[0].length", but I can't figure out how to do that. Thanks!

    import javax.swing.JOptionPane;
import java.util.Scanner;

public class arraytest {
public static void main(String[] args)
{

    int i = 0;
    String classInput;

    String[][] classNames = {
              {"CIS 280", "ACC 212", "HIS 300"},
              {"Tue 7:30", "Thu 2:30", "Fri 1:00" }
            };


classInput = JOptionPane.showInputDialog("Please input a class name: ");


for (i = 0; classNames[0].length; ++i) // problem line
   if(classNames[0][i].equals(classInput)) 
   {
       System.out.println("class time:" + classNames[1][i]);

   }
}

}

Answer 1

You probably wanted to compare i to classNames[0].length to provide the necessary boolean argument. Providing just classNames[0].length is just an int .

for (i = 0; i < classNames[0].length; ++i)

Answer 2

我想你的意思是：

for (i = 0; i < classNames[0].length; i++)

Answer 3

import javax.swing.JOptionPane;
import java.util.Scanner;

public class arraytest {
public static void main(String[] args)
{

    int i = 0;
    String classInput;

    String[][] classNames = {
              {"CIS 280", "ACC 212", "HIS 300"},
              {"Tue 7:30", "Thu 2:30", "Fri 1:00" }
            };


classInput = JOptionPane.showInputDialog("Please input a class name: ");


for (i = 0; i<classNames[0].length; ++i) // problem line
   if(classNames[0][i].equals(classInput)) 
   {
       System.out.println("class time:" + classNames[1][i]);

   }
}

}

this will solve your error you just forgot the i<