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());
}
}
问题解决的步骤和错误: