不少程序员都会碰到的三个面试题

1. 求从10到100中能被3或5整除的数的和

int sum = 0;

for(int i = 10; i <= 100; i++) if( i % 3 == 0 || i % 5 == 0) sum += i;

System.out.println(sum);

2. 将一个字符串逆序，不要使用反转函数

String message = "he saw a racecar";

StringBuilder rev = new StringBuilder();

for(int i = message.length()-1; i >= 0; i--) rev.append(message.charAt(i));

System.out.println(rev.toString());

3. 反转一个栈

import java.util.*;

public class MyProgram extends com.ktbyte.submit.Coder {

public static void main(String[] args) {

Stack items = new Stack();

items.push("he"); //he is at the bottom of the stack

items.push("saw");

items.push("a");

items.push("racecar");

reverseStack(items); //now he is at the top

//print in order pushed:

while(items.size()>0) System.out.println(items.pop());

}

public static void reverseStack(Stack stack) {

Queue rev = new LinkedList();

while(stack.size()>0) rev.offer(stack.pop());

while(rev.size()>0) stack.push(rev.poll());

}

}