java - 我该如何解决这个问题我一直得到零作为我的答案而不是我的条件

Question

我该如何解决这个问题。我总是得到零作为我的答案，而不是我的条件。在java的学校评分系统中，我的最终答案一直是零。 IDE 不会检查我的代码，它只会读取变量已初始化的内容，而不是输入的内容。

public class task_3 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub



        int Grades = 0;
        JOptionPane.showInputDialog("Enter marks");
        // JOptionPane.showInputDialog(Grades);

        if (Grades >= 85 && Grades <= 100) {
            JOptionPane.showMessageDialog(null, "your Grade is HD");
        } else {
            if (Grades >= 75 && Grades <= 85) {
                JOptionPane.showMessageDialog(null, "your Grade is D");
            } else {
                if (Grades >= 65 && Grades <= 75) {
                    JOptionPane.showMessageDialog(null, "your Grade is C");
                } else {
                    if (Grades >= 55 && Grades <= 65) {
                        JOptionPane.showMessageDialog(null, "your Grade is P");
                    } else {
                        if (Grades <= 55) {
                            JOptionPane.showMessageDialog(null, "your Grade is F");
                        } else if (Grades > 100) {
                            JOptionPane.showMessageDialog(null, "error");
                        }
                    }
                }

            }
        }
    }
}

Answer 1

您不接受用户的输入。此接受的输入应在条件开始之前在 Grades 中设置。试试这个:

int Grades =0 ;
String input;
input= JOptionPane.showInputDialog("Enter marks" );
Grades=Integer.parseInt(input);

//now apply your if-else conditions
// I tried simplifying your conditions
       if (Grades>=85 && Grades<=100) {
           JOptionPane.showMessageDialog(null, "your Grade is HD");
       }
       else if (Grades>=75 && Grades<=85) {
               JOptionPane.showMessageDialog(null, "your Grade is D");
           }
       else if (Grades>=65 && Grades<75) {
                   JOptionPane.showMessageDialog(null, "your Grade is C");
               }
       else if (Grades>=55 && Grades<65) {
                       JOptionPane.showMessageDialog(null, "your Grade is P");
                   }
        else if (Grades<55) {
                           JOptionPane.showMessageDialog(null, "your Grade is F");
                       }
         else if ( Grades>100) {
                           JOptionPane.showMessageDialog(null,"error");
                           }
                       }
                   }

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