我希望这个程序向用户询问字符串和字符,然后告诉用户字符中的字符串数。
这是代码:
import java.util.Scanner; // Needed for the Scanner Class
/*
This program ask you to enter a string and a character and then tells you how many times the character appears in the string.
*/
public class PC5
{ public static void main(String[] args) throw StringIndexOutOfBoundsException
{
int times = 0; // To keep track of the times the charcater appears in the String
String str1; // To get the string you want to check
String str2; // To get the string for the character you want to check in the String.
char myChar; // To get the character from str2
Scanner keyboard = new Scanner(System.in);
// Get the string you want to check
System.out.print("Enter the string you want to check: ");
str1 = keyboard.nextLine();
// To get the charcater
System.out.print("Enter the character you want to check: ");
str2 = keyboard.nextLine();
myChar = str2.charAt(0);
for (int i = 0; i < str1.length(); i++)
{
if (str2.charAt(i) == myChar)
times += 1;
}
System.out.println("The number of times the character appears in the string is: " + times);
}
}
运行此程序时出现此异常:
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 1
at java.lang.String.charAt(String.java:695)
at PC5.main(PC5.java:36)
感谢您的帮助。
答案 0 :(得分:1)
你可能意味着
if (str1.charAt(i) == myChar)
而不是
if (str2.charAt(i) == myChar)
当您在str1
的长度上进行迭代时,期望str2.length
等于1
答案 1 :(得分:0)
你可以尝试一些更简洁的东西,利用一些String方法:
package com.example.count;
import java.util.Scanner; //需要扫描仪类
/ *
此程序要求您输入字符串和字符,然后告诉您字符在字符串中出现的次数。
* /
公共类PC5 {
public static void main(String[] args)
{
int times = 0; // To keep track of the times the charcater appears in
// the String
String str1; // To get the string you want to check
String str2; // To get the string for the character you want to check in
// the String.
Scanner keyboard = new Scanner(System.in);
// Get the string you want to check
boolean stopping = false;
while (!stopping) {
System.out
.print("Enter the string you want to check: (enter 'end' to stop)");
str1 = keyboard.nextLine();
stopping = "end".equalsIgnoreCase(str1.trim());
if (!stopping) {
// To get the character
System.out.print("Enter the character you want to check: ");
str2 = keyboard.nextLine();
if (str2.length() > 1) {
str2 = str2.substring(0, 1);
}
times = 0;
int loc = -1;
while ((loc = str1.indexOf(str2, loc + 1)) > -1) {
times++;
}
System.out.println("Results: '" + str2 + "' appears " + times
+ " times in string " + str1);
}
}
keyboard.close();
System.out.println("Thanks");
}
}