C++ Day 4

 Great progress! Let’s jump into Day 4 of C++ learning. Today, you'll explore arrays, strings, and basic loops with data structures.

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C++ Day 4: Arrays and Strings

🔹 1. Arrays

An array is a collection of elements of the same data type, stored in contiguous memory locations.

✅ Declaration:

int numbers[5];         // uninitialized
int scores[5] = {10, 20, 30, 40, 50};  // initialized

✅ Accessing Elements:

std::cout << scores[2];  // Output: 30

✅ Looping Through an Array:

for (int i = 0; i < 5; i++) {
    std::cout << scores[i] << " ";
}

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🔹 2. Multidimensional Arrays

✅ Example: 2D Array (Matrix)

int matrix[2][3] = {
    {1, 2, 3},
    {4, 5, 6}
};

✅ Accessing:

std::cout << matrix[1][2]; // Output: 6

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🔹 3. Strings in C++

C++ offers two ways to handle strings:

✅ C-style strings (char arrays)

char name[] = "Alice";
std::cout << name;

✅ C++ string class (recommended)

#include <string>

std::string name = "Alice";
std::cout << name;

✅ String Operations:

std::string s1 = "Hello";
std::string s2 = "World";
std::string result = s1 + " " + s2;
std::cout << result; // Output: Hello World

✅ Useful Functions:

s.length();      // returns length
s.substr(0, 3);  // returns substring
s.find("lo");    // returns index of first match
s.append("!");   // appends to the end

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🔹 4. Common Array/String Problems

• Find the maximum or minimum in an array

• Calculate sum/average

• Reverse a string or array

• Count vowels/consonants in a string

• Sort an array (will cover later in depth)

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✅ Summary for Day 4:

• You learned how to declare, initialize, and use arrays.

• You practiced with both 1D and 2D arrays.

• You learned the difference between C-style strings and C++ strings, and basic operations.