如何打印n个数字的总和？（How to print summation of n numbers?）

问题描述 (Problem Description)

如何打印数字总和？

解决方案 (Solution)

下面的示例演示了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);
   }
}

结果 (Result)

上面的代码示例将产生以下结果。

Sum=1275

以下是前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 50is1275