C++ Programming Labs

Lab 19: Lambda Expressions

Expert

Coding Challenge

Your Task: Learn to write lambda expressions - anonymous inline functions. Lambdas are powerful for callbacks, algorithms, and functional programming.

Detailed Requirements:
1. Basic lambda syntax:

[capture](parameters) -> return_type {
    // body
}

   • [] - capture clause (variables from outer scope)
   • () - parameters (like regular functions)
   • -> type - return type (optional, usually inferred)

2. Simple lambda examples:

auto greet = []() { cout << "Hello!"; };
greet();  // Prints: Hello!

auto add = [](int a, int b) { return a + b; };
cout << add(3, 4);  // Prints: 7

3. Capture modes:

int x = 10;
auto byValue = [x]() { return x; };      // Copy
auto byRef = [&x]() { x++; };            // Reference
auto allByValue = [=]() { return x; };   // All by copy
auto allByRef = [&]() { x++; };          // All by ref

4. Use with STL algorithms:

vector nums = {1, 2, 3, 4, 5};
for_each(nums.begin(), nums.end(), [](int n) {
    cout << n * 2 << " ";
});

Expected Output:

Simple lambda: 7
With capture: 15
Modified by ref: 11
Doubled: 2 4 6 8 10

Requirements Checklist

Create a basic lambda with [] syntax

Create a lambda with parameters

Use capture by value [x]

Use capture by reference [&x]

Store lambda in auto variable

Use lambda with for_each algorithm

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    // TODO: Create simple lambda with parameters
    // auto add = [](int a, int b) { return a + b; };
    // cout << "Simple lambda: " << add(3, 4) << endl;
    
    // TODO: Lambda with capture by value
    // int x = 10;
    // auto addX = [x](int n) { return n + x; };
    // cout << "With capture: " << addX(5) << endl;
    
    // TODO: Lambda with capture by reference
    // auto increment = [&x]() { x++; };
    // increment();
    // cout << "Modified by ref: " << x << endl;
    
    // TODO: Use lambda with for_each
    // vector<int> nums = {1, 2, 3, 4, 5};
    // cout << "Doubled: ";
    // for_each(nums.begin(), nums.end(), [](int n) {
    //     cout << n * 2 << " ";
    // });
    // cout << endl;
    
    return 0;
}

Output

// Click "Run Code" to compile and execute // Your program output will appear here

Hints & Tips

• Basic: auto f = []() { };

• With params: auto f = [](int x) { return x; };

• Capture value: [x], reference: [&x]

• Capture all: [=] by value, [&] by ref

Progress: 0/6

Score: 0/100

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Lab 20: STL Algorithms

Expert

Coding Challenge

Your Task: Master the C++ Standard Template Library algorithms. These powerful functions work with iterators and simplify common operations.

Detailed Requirements:
1. Include algorithm header:
#include <algorithm>

2. Sorting algorithms:

vector v = {5, 2, 8, 1, 9};
sort(v.begin(), v.end());           // Ascending
sort(v.begin(), v.end(), greater()); // Descending

3. Searching algorithms:

auto it = find(v.begin(), v.end(), 5);
if (it != v.end()) cout << "Found!";

bool exists = binary_search(v.begin(), v.end(), 5);

4. Transformation algorithms:

// Transform each element
transform(v.begin(), v.end(), v.begin(), 
    [](int x) { return x * 2; });

// Copy elements matching condition
vector evens;
copy_if(v.begin(), v.end(), back_inserter(evens),
    [](int x) { return x % 2 == 0; });

5. Numeric algorithms:

#include 
int sum = accumulate(v.begin(), v.end(), 0);
int count = count_if(v.begin(), v.end(), 
    [](int x) { return x > 5; });

Expected Output:

Sorted: 1 2 3 4 5
Found 3 at position 2
Sum: 15
Count > 2: 3

Requirements Checklist

Include algorithm header

Use sort() to sort a vector

Use find() to search for element

Use transform() or for_each()

Use accumulate() for sum

Use count_if() with predicate

#include <iostream>
#include <vector>
// TODO: Include algorithm and numeric headers
// #include <algorithm>
// #include <numeric>

using namespace std;

int main() {
    // vector<int> nums = {5, 2, 8, 1, 3};
    
    // TODO: Sort the vector
    // sort(nums.begin(), nums.end());
    // cout << "Sorted: ";
    // for (int n : nums) cout << n << " ";
    // cout << endl;
    
    // TODO: Find an element
    // auto it = find(nums.begin(), nums.end(), 3);
    // if (it != nums.end()) {
    //     cout << "Found 3 at position " << (it - nums.begin()) << endl;
    // }
    
    // TODO: Calculate sum with accumulate
    // int sum = accumulate(nums.begin(), nums.end(), 0);
    // cout << "Sum: " << sum << endl;
    
    // TODO: Count elements matching condition
    // int count = count_if(nums.begin(), nums.end(), 
    //     [](int x) { return x > 2; });
    // cout << "Count > 2: " << count << endl;
    
    return 0;
}

Output

// Click "Run Code" to compile and execute // Your program output will appear here

Hints & Tips

• Sort: sort(v.begin(), v.end());

• Find: find(v.begin(), v.end(), value);

• Sum: accumulate(v.begin(), v.end(), 0);

• Count: count_if(begin, end, predicate);

Progress: 0/6

Score: 0/100

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Lab 21: Inheritance & Polymorphism

Expert

Coding Challenge

Your Task: Implement inheritance and polymorphism - core OOP concepts. Create a class hierarchy with virtual functions.

Detailed Requirements:
1. Create a base class with virtual function:

class Animal {
public:
    virtual void speak() {
        cout << "Animal sound" << endl;
    }
    virtual ~Animal() {}  // Virtual destructor
};

• virtual enables runtime polymorphism
• Always use virtual destructor in base classes

2. Create derived classes:

class Dog : public Animal {
public:
    void speak() override {
        cout << "Woof!" << endl;
    }
};

class Cat : public Animal {
public:
    void speak() override {
        cout << "Meow!" << endl;
    }
};

• : public Animal inherits from Animal
• override ensures we're overriding a virtual function

3. Use polymorphism:

Animal* pet = new Dog();
pet->speak();  // Prints "Woof!" (dynamic dispatch)
delete pet;

Expected Output:

Dog says: Woof!
Cat says: Meow!
Using base pointer:
Woof!
Meow!

Requirements Checklist

Create base class with virtual function

Add virtual destructor to base class

Create derived class using : public

Override virtual function with override keyword

Create second derived class

Demonstrate polymorphism with base pointer

#include <iostream>
using namespace std;

// TODO: Create base class Animal
// class Animal {
// public:
//     virtual void speak() {
//         cout << "Animal sound" << endl;
//     }
//     virtual ~Animal() {}
// };


// TODO: Create Dog class inheriting from Animal
// class Dog : public Animal {
// public:
//     void speak() override {
//         cout << "Woof!" << endl;
//     }
// };


// TODO: Create Cat class inheriting from Animal
// class Cat : public Animal {
// public:
//     void speak() override {
//         cout << "Meow!" << endl;
//     }
// };


int main() {
    // TODO: Create objects and test
    // Dog dog;
    // Cat cat;
    // cout << "Dog says: "; dog.speak();
    // cout << "Cat says: "; cat.speak();
    
    // TODO: Demonstrate polymorphism
    // cout << "Using base pointer:" << endl;
    // Animal* pet1 = new Dog();
    // Animal* pet2 = new Cat();
    // pet1->speak();
    // pet2->speak();
    // delete pet1;
    // delete pet2;
    
    return 0;
}

Output

// Click "Run Code" to compile and execute // Your program output will appear here

Hints & Tips

• Virtual: virtual void func() { }

• Inherit: class Derived : public Base { }

• Override: void func() override { }

• Always use virtual ~Base() {}

Progress: 0/6

Score: 0/100

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Lambdas, STL Algorithms & Inheritance - Module 7

Requirements Checklist

Lab Results

Requirements Checklist

Lab Results

Requirements Checklist

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