题目

创建一个“你在玩班卓琴吗？”这个问题回答的函数。
如果您的名字以字母“R”或小写字母“r”开头，那么您正在玩班卓琴！

该函数将名称作为其唯一参数，并返回以下字符串之一：

name + " plays banjo" 
name + " does not play banjo"

给出的名称始终是有效的字符串。

测试用例：

import org.junit.Test;
import static org.junit.Assert.assertEquals;

public class BanjoExampleTest {
  @Test
  public void PeopleThatPlayBanjo() {
    assertEquals( "Nope!" , Banjo.areYouPlayingBanjo("Martin"), "Martin does not play banjo");
    assertEquals( "Nope!" , Banjo.areYouPlayingBanjo("Rikke"), "Rikke plays banjo");
  }
}

解题

1.判断首字母是否为R或r
2.是则返回plays banjo，否则返回dose not plays banjo
3.用三元运算符就可以解决

public class Banjo {
  public static String areYouPlayingBanjo(String name) {
    return name.charAt(0) == 'R' || name.charAt(0) == 'r' ? name + " plays banjo" : name + " does not play banjo";
  }
}

Other

public class Banjo 
{
  public static String areYouPlayingBanjo(String name) 
  {
    if( name.toUpperCase().startsWith("R") )
      return name + " plays banjo";
    else
      return name + " does not play banjo";
  }
}

后记

首字母可以.charAt(0)或者.startsWith("R")再或者.substring(0,1)，我觉得还是startsWith()好一些，会直接返回Boolean值。