Introduction to C++ Fundamentals: Syntax, Structure, and Basic Compon… (

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* Introduction to C++ Fundamentals: Syntax, Structure, and Basic Components

* Add content of day 08 subhadipbhowmik#504

docs/day-02/first-cpp-program.md

@@ -86,7 +86,222 @@ Examples:
  - `cout << "Hello, World!" << endl;` - Prints "Hello, World!" to the console.
  - `if (age >= 18) { ... }` - Conditional statement to check if age is greater than or equal to 18 and execute code within the block if true.
  - `for (int i = 0; i < 3; i++) { ... }` - Loop that iterates three times.
-6. Comments (Optional):
+
+ Additional Syntax Elements:
+
+
+5. Semicolons (;):
+
+In C++, semicolons are used to terminate most statements.
+They act as a separator between different instructions.
+Example:
+cppCopyint x = 5;
+cout << "Hello";
+
+Forgetting semicolons is a common mistake for beginners and can lead to compilation errors.
+
+6. Curly Braces ({}):
+
+Used to group multiple statements into a single block.
+Essential for defining the scope of functions, loops, and conditional statements.
+Also used to define the body of classes and namespaces.
+Example:
+cppCopyif (condition) {
+    // Multiple statements can be placed here
+    statement1;
+    statement2;
+}
+
+
+7. Parentheses ():
+
+Used in function declarations and calls to enclose parameters.
+Required in conditional statements and loops to enclose conditions.
+Example:
+cppCopyint add(int a, int b) {
+    return a + b;
+}
+
+if (x > 0) {
+    // Do something
+}
+
+
+
+Data Types:
+
+C++ provides several built-in data types:
+
+Integer types:
+
+int: Whole numbers (e.g., -5, 0, 42)
+short: Smaller range integer
+long: Larger range integer
+unsigned variations of the above
+
+
+Floating-point types:
+
+float: Single-precision decimal numbers
+double: Double-precision decimal numbers
+
+
+Character types:
+
+char: Single character (e.g., 'A', '7', '$')
+
+
+Boolean type:
+
+bool: True or false values
+
+
+Derived types:
+
+arrays: Collections of elements of the same type
+pointers: Store memory addresses
+references: Aliases for existing variables
+
+
+
+Example:
+cppCopyint age = 25;
+float pi = 3.14159f;
+char grade = 'A';
+bool isStudent = true;
+int numbers[5] = {1, 2, 3, 4, 5};  // Array
+int* ptr = &age;  // Pointer
+int& ageRef = age;  // Reference
+
+8. Operators:
+
+C++ provides various types of operators:
+a. Arithmetic operators:
+
+Addition (+), Subtraction (-), Multiplication (*), Division (/), Modulus (%)
+Example: int result = 10 + 5 * 2;  // result is 20
+
+b. Comparison operators:
+
+Equal to (==), Not equal to (!=), Greater than (>), Less than (<),
+Greater than or equal to (>=), Less than or equal to (<=)
+Example: if (age >= 18) { cout << "Adult"; }
+
+c. Logical operators:
+
+AND (&&), OR (||), NOT (!)
+Example: if (age > 18 && hasLicense) { cout << "Can drive"; }
+
+d. Assignment operators:
+
+Simple assignment (=)
+Compound assignments (+=, -=, *=, /=, %=)
+Example:
+cppCopyint x = 5;
+x += 3;  // Equivalent to x = x + 3;
+
+
+
+9. Control Structures:
+
+Control structures direct the flow of program execution:
+a. if-else statements:
+cppCopyif (condition) {
+    // Code executed if condition is true
+} else if (another_condition) {
+    // Code executed if another_condition is true
+} else {
+    // Code executed if all conditions are false
+}
+b. switch statements:
+cppCopyswitch (variable) {
+    case value1:
+        // Code for value1
+        break;
+    case value2:
+        // Code for value2
+        break;
+    default:
+        // Code if no case matches
+}
+c. Loops:
+
+for loop: Used when number of iterations is known
+cppCopyfor (int i = 0; i < 5; i++) {
+    cout << i << " ";
+}
+
+while loop: Executes while a condition is true
+cppCopywhile (condition) {
+    // Code to repeat
+}
+
+do-while loop: Executes at least once, then repeats while condition is true
+cppCopydo {
+    // Code to repeat
+} while (condition);
+
+
+
+10. Functions:
+
+Functions are reusable blocks of code:
+
+Function declaration: Tells compiler about function name, return type, and parameters
+Function definition: Provides the actual body of the function
+Example:
+cppCopy// Declaration
+int add(int a, int b);
+
+// Definition
+int add(int a, int b) {
+    return a + b;
+}
+
+// Function call
+int result = add(5, 3);
+
+
+Function overloading: Multiple functions can have the same name if they differ in parameter types or number.
+
+11. Basic Input/Output:
+
+C++ uses streams for input/output operations:
+
+cout for output:
+cppCopycout << "Hello, " << name << "!";
+
+cin for input:
+cppCopyint age;
+cin >> age;
+
+Formatting output:
+cppCopy#include <iomanip>
+cout << fixed << setprecision(2) << 3.14159;  // Outputs 3.14
+
+
+
+12. Header Files:
+
+Header files contain declarations of functions and variables:
+
+Standard library headers: <iostream>, <string>, <vector>, etc.
+User-defined headers: Created for custom libraries
+Usage:
+cppCopy#include <iostream>  // Angular brackets for standard headers
+#include "myheader.h"  // Quotes for user-defined headers
+
+
+
+13. Compilation Process:
+
+C++ programs go through several stages before execution:
+
+Preprocessing: Handles directives like #include and #define
+Compilation: Converts C++ code to object code
+Linking: Combines object code with libraries to create an executable
+
+14. Comments (Optional):
 
 - Lines starting with `//` (single line comment) or `/* ... */` (multi-line comment).
 - Provide explanations within the code for better understanding.

docs/day-08/_category_.json

@@ -0,0 +1,7 @@
+{
+    "label": "Day 08",
+    "position": 8,
+    "link": {
+      "type": "generated-index"
+    }
+  }

docs/day-08/strings.md

@@ -0,0 +1,159 @@
+1. Introduction to Strings in C++
+
+A string is a sequence of characters. In C++, there are two main ways to work with strings:
+
+    1. C-style strings (character arrays)
+    2. The C++ string class
+
+
+2. C-style Strings
+
+C-style strings are inherited from the C language. They are essentially arrays of characters ending with a null character '\0'.
+Example:
+
+cppCopychar str[] = "Hello";  // Equivalent to {'H','e','l','l','o','\0'}
+Pros:
+
+Low-level control
+Compatibility with C code
+
+Cons:
+
+Prone to buffer overflow errors
+Limited built-in functionality
+
+
+3. C++ String Class
+
+The C++ string class is part of the Standard Template Library (STL). It's much more powerful and safer to use than C-style strings.
+To use the string class, include the <string> header:
+cppCopy#include <string>
+using namespace std;
+
+string str = "Hello, World!";
+
+4. String Declaration and Initialization
+
+You can declare and initialize strings in several ways:
+cppCopystring s1;               // Empty string
+string s2 = "Hello";     // Initialize with a string literal
+string s3("World");      // Initialize using constructor
+string s4(5, 'A');       // Initialize with 5 'A' characters: "AAAAA"
+string s5 = s2;          // Copy initialization
+
+5. String Operations
+
+a. Concatenation:
+cppCopystring a = "Hello";
+string b = "World";
+string c = a + " " + b;  // c is "Hello World"
+
+b. Appending:
+cppCopystring str = "Hello";
+str += " World";         // str is now "Hello World"
+
+c. Accessing characters:
+cppCopystring str = "Hello";
+char ch = str[0];        // ch is 'H'
+
+d. Length:
+cppCopystring str = "Hello";
+int len = str.length();  // or str.size(); both return 5
+
+e. Substring:
+cppCopystring str = "Hello, World!";
+string sub = str.substr(7, 5);  // sub is "World"
+
+f. Finding:
+cppCopystring str = "Hello, World!";
+size_t pos = str.find("World");  // pos is 7
+
+g. Replacing:
+cppCopystring str = "Hello, World!";
+str.replace(7, 5, "C++");  // str is now "Hello, C++!"
+
+6. String Input/Output
+
+a. Output:
+cppCopystring str = "Hello";
+cout << str << endl;
+
+b. Input:
+cppCopystring name;
+cout << "Enter your name: ";
+cin >> name;  // Reads until whitespace
+
+c. Reading a line:
+cppCopystring line;
+getline(cin, line);  // Reads entire line, including spaces
+
+7. String Comparison
+
+You can compare strings using relational operators:
+cppCopystring s1 = "apple";
+string s2 = "banana";
+if (s1 < s2) {
+    cout << "apple comes before banana" << endl;
+}
+
+8. String Conversion
+
+a. To C-style string:
+cppCopystring str = "Hello";
+const char* cstr = str.c_str(); 
+
+b. Number to string:
+cppCopyint num = 123;
+string str = to_string(num);
+
+c. String to number:
+cppCopystring str = "123";
+int num = stoi(str);  // string to int
+double d = stod(str); // string to double
+
+9. String Iteration
+
+You can iterate through a string using range-based for loop or traditional for loop:
+cppCopystring str = "Hello";
+for (char c : str) {
+    cout << c << " ";
+}
+
+10. String Modifiers
+
+a. Insert:
+cppCopystring str = "Hello";
+str.insert(5, " World");  // str is now "Hello World"
+
+b. Erase:
+cppCopystring str = "Hello World";
+str.erase(5, 6);  // str is now "Hello"
+
+c. Clear:
+cppCopystring str = "Hello";
+str.clear();  // str is now an empty string
+
+11. String Capacity
+
+a. Resize:
+cppCopystring str = "Hello";
+str.resize(10, '!');  // str is now "Hello!!!!!"
+
+b. Capacity:
+cppCopystring str = "Hello";
+cout << str.capacity();  // Prints the current capacity
+
+12. Advanced String Operations
+
+a. Regular expressions (C++11 and later):
+cppCopy#include <regex>
+string str = "Hello, 123";
+regex pattern("\\d+");
+if (regex_search(str, pattern)) {
+    cout << "String contains digits" << endl;
+}
+
+b. String view (C++17):
+cppCopy#include <string_view>
+string_view sv = "Hello, World!";
+cout << sv.substr(0, 5);  // Efficient substring operation