Question

这是一个等级检查程序，用户应该输入0-100等级，并说明他们得到的等级。我看过其他地方但找不到任何东西。

提前致谢

import java.util.*;

public class grading{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    System.out.println("Please input grade");
    int grade = scan.nextInt();
    if (grade > 100){
      System.out.println("Sorry please put a number between 0-100");
    }
    else if (grade > 90){
      grade = "A";
      System.out.println("This student recieved " + grade " for his/her grade");
    }
    else if (grade > 75){
      grade = "B";
      System.out.println("This student recieved " + grade " for his/her grade");
    }
    else if (grade > 49){
      grade = "C";
      System.out.println("This student recieved " + grade " for his/her grade");
    }
    else{
      grade = "F";
      System.out.println("This student recieved " + grade " for his/her grade");
    }

  }

}

Answer 1

在您的每个println语句中，您都错过了+与字符串最后部分之间的grade连接运算符。

您似乎也在使用grade两个不同的东西，即用户输入的整数和串联中使用的字符串。

后者可能应该是一个独特的变量，如：

int grade = scan.nextInt();
String strGrade;

:

else if (grade > 90){
  strGrade = "A";
  System.out.println("This student received " + strGrade + " for his/her grade");
}

另外，为了在输入有符号整数时的完整性，你应该也可以使第一个检查句柄为负数：

if ((grade < 0) || (grade > 100)) {
  System.out.println("Sorry please put a number between 0-100");
}

此外，您可以重构每个条件块中的重复代码，从而使程序更具可读性：

import java.util.*;

public class Grading {
  public static void main(String[] args) {
    // Get the grade.

    Scanner scan = new Scanner(System.in);
    System.out.println("Please input grade");
    int grade = scan.nextInt();

    // Validate grade.

    if ((grade < 0) || (grade > 100)) {
      System.out.println("Sorry please put a number between 0-100");
    } else {
      // If valid, default to F, upgrade based on grade.

      String strGrade = "F";
      if      (grade > 90) strGrade = "A";
      else if (grade > 75) strGrade = "B";
      else if (grade > 49) strGrade = "C";

      // Output the results.

      System.out.println("This student received " + strGrade + " for his/her grade");
    }
  }
}

Answer 2

import java.util.*;

public class grading{

public static void main(String[] args){

Scanner scan = new Scanner(System.in);
System.out.println("Please input grade");
int grade = scan.nextInt();
String gradeLevel = "";

if (grade > 100){
  System.out.println("Sorry please put a number between 0-100");
}
else if (grade > 90){
    gradeLevel = "A";
  System.out.println("This student recieved " + gradeLevel + " for his/her grade");
}
else if (grade > 75){
    gradeLevel = "B";
  System.out.println("This student recieved " + gradeLevel + " for his/her grade");
}
else if (grade > 49){
    gradeLevel = "C";
  System.out.println("This student recieved " + gradeLevel + " for his/her grade");
}
else{
    gradeLevel = "F";
  System.out.println("This student recieved " + gradeLevel + " for his/her grade");
}

}

Answer 3

在需要+的字符串之间连接

我是Java的新手 - 非法的表达开始和＆＃39;（＆＃39;和＆＃39;）＆＃39;预期

3 个答案: