Java 示例 - 数字求和

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  问题描述

  如何打印数字的总和？
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  解决方案

  以下示例演示如何使用堆栈的概念添加前 n 个自然数。

  
  import java.io.IOException;
  public class AdditionStack {
     static int num;
     static int ans;
     static Stack theStack;
     public static void main(String[] args)
     
     throws IOException {
        num = 50;
        stackAddition();
        System.out.println("Sum = " + ans);
     }
     public static void stackAddition() {
        theStack = new Stack(10000); 
        ans = 0; 
        while (num > 0) {
           theStack.push(num); 
           --num; 
        }
        while (!theStack.isEmpty()) {
           int newN = theStack.pop(); 
           ans += newN; 
        }
     }
  }
  class Stack {
     private int maxSize; 
     private int[] data;
     private int top; 
     public Stack(int s) {
        maxSize = s;
        data = new int[maxSize];
        top = -1;
     }
     public void push(int p) {
        data[++top] = p;
     }
     public int pop() {
        return data[top--];
     }
     public int peek() {
        return data[top];
     }
     public boolean isEmpty() {
        return (top == -1);
     }
  }
  

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  结果

  上面的代码示例将产生以下结果。

  
  Sum = 1275
  

  下面是前n个自然数的另一个例子

  
  public class Demo {
     public static void main(String[] args) {
        int sum = 0;
        int n = 50;
        for (int i = 1; i <= n; i++) {
           sum = sum + i;
        } 
        System.out.println("The Sum Of " + n + "is" + sum);
     }
  }
  

  上面的代码示例将产生以下结果。

  
  The Sum Of 50 is 1275