java Java String charAt()方法示例

Java String charAt()方法示例

原文:https://www . geesforgeks . org/Java-string-charat-method-example/

Java String charAt() 方法返回指定索引处的字符。索引值应该介于 0 和 length()-1 之间。 签名:

 public char charAt(int index)

参数:

 index- Index of the character to be returned.

返回:

 returns character at the specified position.

例外:

 StringIndexOutOfBoundsException- If index is 
 negative or greater then the length of the 
 String.

示例:展示 charAt() 方法的工作

// Java program to demonstrate
// working of charAt() method

class Gfg {
    public static void main(String args[])
    {
        String s = "Welcome! to Geeksforgeeks Planet";

        char ch = s.charAt(3);
        System.out.println(ch);

        ch = s.charAt(0);
        System.out.println(ch);
    }
}

Output:

c
W

// Java program to demonstrate
// working of charAt() method

class Gfg {
    public static void main(String args[])
    {
        String s = "abc";

        char ch = s.charAt(4);
        System.out.println(ch);
    }
}

Output:

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 4
    at java.lang.String.charAt(String.java:658)
    at Gfg.main(File.java:9)