# Java Examples - Summation of Numbers

## Problem Description:

How to print summation of n numbers?

## Solution:

Following example demonstrates how to add first n natural numbers by using the concept of stack .

```import java.io.IOException;

static int num;
static int ans;
static Stack theStack;
public static void main(String[] args)
throws IOException {
num = 50;
System.out.println("Sum=" + ans);
}
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);
}
}
```

## Result:

The above code sample will produce the following result.

```Sum=1225
```

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