Question

如何删除此错误？请任何人帮忙我收到错误＆＃34;运算符+未定义参数类型java.util.Scanner＆＃34; 不知道为什么会出现这种情况？

包com.learn.java;

import java.util.Scanner;

public class GradeCalculator {

    public static void main(String[] args) {

        System.out.println("Enter marks of MATHS");
        Scanner math = new Scanner(System.in);
        System.out.println(math.nextFloat());

        System.out.println("Enter marks of ENGLISH");
        Scanner eng = new Scanner(System.in);
        System.out.println(eng.nextFloat());

        System.out.println("Enter marks of SOCIALSCIENCES");
        Scanner socialScience = new Scanner(System.in);
        System.out.println(socialScience.nextFloat());

        System.out.println("Enter marks of SCIENCE");
        Scanner science = new Scanner(System.in);
        System.out.println(science.nextFloat());

        float avgMarks = averageCalculator(math, eng, socialScience, science);
        System.out.println(avgMarks);
        calculatePerformanceGrades(avgMarks);

    }

    private static float averageCalculator(Scanner math, Scanner eng,
            Scanner socialScience, Scanner science) {
        float averageMarks;
        averageMarks=((math + eng + socialScience + science) / 4);//getting an error here(The operator + is undefined for the argument type(s) java.util.Scanner)
        return averageMarks;

    }

    private static void calculatePerformanceGrades(float avgMarks) {
        if (avgMarks < 40) {
            System.out.println("Poor");
        } else if (avgMarks >= 40 && avgMarks < 59) {
            System.out.println("Average");
        } else if (avgMarks >= 60 && avgMarks < 79) {
            System.out.println("Good");
        } else if (avgMarks >= 80 && avgMarks < 89) {
            System.out.println("Very Good ");
        } else if (avgMarks >= 90 && avgMarks <= 100) {
            System.out.println("Excellent");
        }
    }
}

请帮助解决问题。

Answer 1

您无法使用扫描仪添加数据并在以后查找平均值。你可以只对数字执行算术运算，即整数，浮点数等。而是定义你的方法接受像import {Component, NgModule} from '@angular/core' import {BrowserModule} from '@angular/platform-browser' @Component({ selector: 'my-app', template: ` <div> <h2 *ngIf="names && names.length">Hello {{names[0]}}</h2> <h2 *ngFor="let n of names">Hi {{n}}</h2> </div> `, }) export class App { constructor() { this.names = []; setTimeout(() => this.names = ['Angular2', 'Name2', 'name3'], 3000); } } @NgModule({ imports: [ BrowserModule ], declarations: [ App ], bootstrap: [ App ] }) export class AppModule {}这样的输入数据类型（我会在这里取float）

double

当您从标准输入（即键盘）获取输入时，您需要捕获该值并将该值发送到方法private static float averageCalculator(float math, float eng, float socialScience, float science) { .... }，如：

averageCalculator

Answer 2

您正在使用扫描仪执行无法完成的算术运算。而是将float参数传递给方法并进行操作。

public static void main(String[] args) {

            System.out.println("Enter marks of MATHS");
            Scanner math = new Scanner(System.in);
            float math1=(math.nextFloat());


            System.out.println("Enter marks of ENGLISH");
            Scanner eng = new Scanner(System.in);
            float eng1 = eng.nextFloat();


            System.out.println("Enter marks of SOCIALSCIENCES");
            Scanner socialScience = new Scanner(System.in);
            float socialScience1= socialScience.nextFloat();

            System.out.println("Enter marks of SCIENCE");
            Scanner science = new Scanner(System.in);
            float science1=  science.nextFloat();


            float avgMarks = averageCalculator(math1, eng1, socialScience1, science1);
            System.out.println(avgMarks);
            calculatePerformanceGrades(avgMarks);

        }

        private static float averageCalculator(float math, float eng,
                float socialScience, float science) {
            float averageMarks;
            averageMarks=((math + eng + socialScience + science) / 4);
            return averageMarks;

        }

        private static void calculatePerformanceGrades(float avgMarks) {
            if (avgMarks < 40) {
                System.out.println("Poor");
            } else if (avgMarks >= 40 && avgMarks < 59) {
                System.out.println("Average");
            } else if (avgMarks >= 60 && avgMarks < 79) {
                System.out.println("Good");
            } else if (avgMarks >= 80 && avgMarks < 89) {
                System.out.println("Very Good ");
            } else if (avgMarks >= 90 && avgMarks <= 100) {
                System.out.println("Excellent");
            }
        }

对于参数类型java.util.Scanner，运算符+未定义

2 个答案: