如何修复我的计数器以正确打印输入 2 的次数？

问题描述

import java.util.Scanner;
public class Grammar
{
    public static void main(String[] args)
    {
        // Ask the user to enter a sentence that uses the word 2 instead of to.
        String theText= "";
        System.out.println("Enter a sentence that uses the word 2 instead of to");
        Scanner input = new Scanner(system.in);
        theText = input.nextLine();
        // Call the method useProperGrammar to process the string according to 
        // the directions.
        System.out.println(useProperGrammar(theText));
        
    }
    
public static String useProperGrammar(String theText)
    {
        String newString="";
        int count = 0;
        for(int i = 0; i < theText.length(); i++)
        {
        count++;
             if (theText.contains("2"))
            {
            String character = theText.substring(i,i+1);
            newString= theText.replace("2","to");
            System.out.println("Fixed "+ count +" grammatical errors:");
            return newString;
            }
            else
            {
                System.out.println("Fixed 0 grammatical errors");
                return theText;
            }
        }
        
        return newString;
       
    }

}

基本上，我试图计算用户输入“2”并被替换的次数 'to' 但无论我输入多少个 2，它总是输出 'Fixed 1 grammatical error' 或（'fixed 0 grammatical errors' 如果没有输入 '2'）。

解决方法

import java.util.Scanner;
public class Grammar {
    public static void main(String[] args){
        // Ask the user to enter a sentence that uses the word 2 instead of to.
        String theText= "";
        System.out.println("Enter a sentence that uses the word 2 instead of to");
        Scanner input = new Scanner(System.in);
        theText = input.nextLine();
        // Call the method useProperGrammar to process the string according to 
        // the directions.
        System.out.println(useProperGrammar(theText));     
    }
    
    public static String useProperGrammar(String theText){
        String newString="";
        int count = 0;
        for(int i = 0; i < theText.length(); i++){
             while (theText.contains("2")){
            count = theText.length() - theText.replaceAll("2","").length();
            String character = theText.substring(i,i+1);
            newString= theText.replace("2","to");
            System.out.println("Fixed "+ count +" grammatical errors:");
            return newString;
            }
        
                System.out.println("Fixed 0 grammatical errors");
                return theText;    
        }
        
        return newString;
       
    }

}

除了上一个答案中已经报告的错误之外，您的代码无法编译，因为您编写了一个没有 if 的 else。

,

你需要像下面这样计算长度

int count = theText.length() - theText.replaceAll("2","").length();

replacell 方法返回对调用此方法的字符串对象进行替换的次数

完整方法

public static String useProperGrammar(String theText)
    {
        String newString="";
        for(int i = 0; i < theText.length(); i++)
        {
       
             if (theText.contains("2"))
            {
            int count = theText.length() - theText.replaceAll("2","to");
            System.out.println("Fixed "+ count +" grammatical errors:");
            
            return newString;
            }
            else
            {
                System.out.println("Fixed 0 grammatical errors");
                return theText;
            }
        }
        
        return newString;
       
    }

,

您可以简单地使用 charAt 函数并在每次返回“2”时增加计数， 它应该是这样的：

int count = 0;
String text = "your text 222";
for(int i = 0; i <= text.length(); i++){
    if(text.charAt(i) == 2){
    count++;
    }
}