如何将一系列字符转换为大写

Question

所以我有

System.out.println ("Initial letters are: " + (firstName.charAt(0)) +(lastName.charAt(0)) );

我想把这2个字符变成大写字母。我试过了

System.out.println ("Initial letters are: " + toUpperCase((firstName.charAt(0))) + toUpperCase((lastName.charAt(0))) );

但这似乎是错误的。

Answer 1

您应该添加Character.toUpperCase('some char')

请参阅

System.out.println ("Initial letters are: " + Character.toUpperCase((firstName.charAt(0))) +Character.toUpperCase((lastName.charAt(0)) ));

这是一个完整的代码：

public class class1 {

public static void main(String[] args) {
    String firstName="some_first_name",lastName="some_last_name";


    System.out.println ("Initial letters are: " + Character.toUpperCase((firstName.charAt(0))) +Character.toUpperCase((lastName.charAt(0)) ));

}

}