Chapter 1: Key C++ Programming Techniques

Learn some vital C++ programming techniques that can help you write cleaner and more efficient code.

1. Include All Standard Libraries at Once

Instead of including each standard library individually, you can simply use #include <bits/stdc++.h>. This is particularly handy during programming competitions where every second counts.

For instance, you can condense this:

#include <iostream>

#include <algorithm>

#include <vector>

#include <string>

#include <stack>

#include <set>

#include <queue>

#include <map>

Into this single line:

#include <bits/stdc++.h>

However, be cautious: <bits/stdc++.h> includes many headers that may not be necessary for your project, which could lead to longer compilation times. Additionally, it's not a standard header in the GNU C++ library, so you may encounter issues with non-GCC compilers, although this is rare.

2. Utilize the Auto Keyword for Type Inference

Starting from C++11, the auto keyword allows you to declare a variable without explicitly defining its type, which can simplify your code, especially when dealing with iterators.

For example:

auto a = 'a';

auto t = true;

auto x = 1;

auto y = 2.0;

3. Employ Range-Based For Loops

The range-based for loop, introduced in C++11, offers a more intuitive way to iterate through collections.

The syntax is as follows:

for (range_declaration : range_expression)

Here’s how to iterate through an array of integers:

int numbers[] = {1, 2, 3, 4, 5};

for (auto number : numbers) {

cout << number << endl;

}

You can also loop through the characters of a string similarly:

string name = "Charlie";

for (auto character : name) {

cout << character << endl;

}

4. Simplify If…Else Statements

You can convert traditional if...else statements into concise one-liners using the ternary operator.

For example, the following code:

int age = 9;

if (age < 18) {

printf("A Child");

} else {

printf("An Adult");

}

Can be neatly rewritten as:

age < 18 ? printf("A Child") : printf("An Adult");

The general syntax for a ternary operator is:

condition ? true_expression : false_expression

While the ternary operator is common in many programming languages, be mindful of overusing it as it can affect code readability.

5. Swap Variables Without an Extra Variable

You can use the XOR operator to swap two variables without needing a third variable. Here’s how:

int a = 1;

int b = 2;

a ^= b ^= a ^= b;

6. Utilize the --> Operator for Loops

Although --> is not a true operator, it can function as a decrementing mechanism in a while loop. For instance, to print numbers from 9 to 1, you can write:

int x = 10;

while (x --> 0) {

printf("%d ", x);

}

This essentially operates as while ((x--) > 0).

7. Prefer Pre-Increment Over Post-Increment

In C++, you can increment a value using either pre-increment (++i) or post-increment (i++). Pre-increment is generally more efficient because it doesn’t create a copy of the variable.

8. Combine Assignment with Function Calls

In C++, you can streamline your code by combining assignment with function calls. Instead of writing:

int i;

i = 10;

printf("%d", i); // prints 10

You can condense it to:

printf("%d", i = 10); // prints 10

That's a wrap on these essential C++ programming tricks!

The first video, titled "How I Program C," provides insights into practical C programming techniques that can be beneficial for learners.

The second video, "C Language Tutorial for Beginners (With Notes)," is a great resource for those starting out with C programming, offering foundational concepts and notes.

Thanks for reading! I hope you find these tips helpful!