package classtext; import java.util.Scanner; public class palindrome { public static boolean recurrence(String s,int len,int n){//定义递归函数 字符串,长度,首元素序号 Scanner in = new Scanner(System.in); if(len<=1||len==len/2||len==(len+1)/2) {//终止条件 return true; } else { if(s.charAt(n)==s.charAt(len-1)) return recurrence(s,--len,++n); //递归 } return false; } public static void main(String[] args) { Scanner in = new Scanner(System.in); String s1 = in.next(); boolean k=recurrence(s1,s1.length(),0); System.out.println(k); } }
找到递归所需的终止条件,整理好框架,到主函数调用即可