Question

所以在我的第五行代码[if(length == 2 || 1)]中，我的错误或我的声明说运算符||未定义参数类型boolean，int。关于我的语法有什么问题以及如何解决它的任何想法？谢谢！

//Write a program that translates a letter grade into a number grade. Letter grades are
//A B C D F, possibly followed by + or -. Their numeric values are 4, 3, 2, 1, and 0.
//There is no F+ or F-. A + increases the numeric value by 0.3, a - decreases it by     0.3.
//However, an A+ has the value 4.0. All other inputs have value –1.
//Enter a letter grade:

//使用方法getNumericGrade的等级。

public class Grade {
private double grade = 0.0;
public double getNumericGrade(String letterGrade){
    int length = letterGrade.length();
    if(length == 2 || 1){
        char startChar = letterGrade.charAt(0);
        char endChar = letterGrade.charAt(1);
        switch(startChar){
        case 'A':
            this.grade = 4.0;
            break;
        case 'B':
            this.grade = 3.0;
            break;
        case 'C':
            this.grade = 2.0;
            break;
        case 'D':
            this.grade = 1.0;
            break;
        case 'F':
            this.grade = 0.0;
            break;
        default:
            this.grade = -1;
        }
    if(length == 2){
        switch(endChar){
        case '-':
            this.grade = this.grade - .3;
            break;
        case '+':
            if(startChar != 'A'){
            this.grade = this.grade + .3;
            }
            break;
        default:
            this.grade = -1;
        }
    }
    if(startChar == 'F' && length != 1){
        this.grade = -1;
    }
    }else{
        this.grade = -1;
    }
    return this.grade;
}

}

Answer 1

这意味着||运算符不带布尔值和int，你必须给它两个布尔表达式。

if(length == 2 || length ==  1)

Answer 2

你想说的是（长度== 1 ||长度== 2）。你现在正在做的是说if（length == 2 OR 1）。前者涉及两个可以评估真或假的逻辑语句，后者一方面涉及逻辑语句，另一方面涉及整数。

计算机不会将长度== 2或1解释为“如果长度为一个或两个则返回true”，而是“（如果长度等于2则返回true）或（整数1）”。

Answer 3

您可以执行以下操作：

if (Arrays.asList(1,2,3).contains(l.lenghth))
   // code

在“if”语句中使用带有字符串长度方法的“或”语句

3 个答案: