// C++ implementation to find the first negative 
// integer in every window of size k
#include <bits/stdc++.h>

using namespace std;

// function to find the first negative 
// integer in every window of size k
void printFirstNegativeInteger(int arr[], int n, int k)
{
	// A Double Ended Queue, Di that will store indexes of 
	// useful array elements for the current window of size k.
	// The useful elements are all negative integers.
	deque<int> Di;

	/* Process first k (or first window) elements of array */
	int i;
	for ( ; i < k; i++)
		// Add current element at the rear of Di
		// if it is a negative integer
		if (arr[i] < 0)
			Di.push_back(i);
	
	// Process rest of the elements, i.e., from arr[k] to arr[n-1]
	for (i=0 ; i < n; i++)
	{
		// if Di is not empty then the element at the
		// front of the queue is the first negative integer
		// of the previous window
		if (!Di.empty())
			cout << arr[Di.front()] << " ";
		
		// else the window does not have a
		// negative integer
		else
			cout << "0" << " ";

		// Remove the elements which are out of this window
		while ( (!Di.empty()) && Di.front() < (i - k + 1))
			Di.pop_front(); // Remove from front of queue

		// Add current element at the rear of Di
		// if it is a negative integer
		if (arr[i] < 0)
			Di.push_back(i);
	}

	// Print the first negative 
	// integer of last window
	if (!Di.empty())
		cout << arr[Di.front()] << " ";
	else
		cout << "0" << " ";	 
	
}

// Driver program to test above functions
int main()
{
	int arr[] = {12, -1, -7, 8, -15, 30, 16, 28};
	int n = sizeof(arr)/sizeof(arr[0]);
	int k = 3;
	printFirstNegativeInteger(arr, n, k);
	return 0;
}
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#include <iostream>
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    cout << "Hello " << name;
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About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}