Create casting.cpp

variable_and_datatypes/casting.cpp

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+// First things first. What IS casting?
+
+// Casting is essentially just converting one data type into another.
+
+// Casting comes in various forms, such as: Implicit casting, explicit casting.
+// Implicit casting means that the compiler automatically converts the variable.
+// Explicit casting means that the programmer explicitly converts the variable using a cast operator.
+
+// Namely, in C++, you can use static_cast, dynamic_cast, const_cast, and reinterpret_cast for explicit casting.
+
+#include <iostream>
+#include <string> // You will see why we need this soon.
+
+int main() {
+    std::cout << "Lets see how a cast works.\n";
+
+    // First, implicit casting...
+    // Take a variable. Say... a floating point variable.
+    float number = 3.14159f;
+    std::cout << "The number is: " << number << "\n";
+    // Now we wanna cast this to an integer.
+    int casted_number = number;
+    std::cout << "The casted number is: " << casted_number << "\n";
+    // Here, the first output will be 3.14159, and the second will be 3.
+    // This is because implicit casting cuts off the decimal part when converting from float to int.
+
+    // Another example of implicit casting...
+    int integer = 98;
+    std::cout << "Integer: " << integer << "\n";
+    // Now, lets cast this integer to a character.
+    char casted_char = integer;
+    std::cout << "Casted Integer: " << casted_char << "\n";
+    // The output will be 'b', because the ASCII character assigned to 98 is 'b'.
+
+
+    // Explicit casting...
+    // Let's take the same float variable.
+    float another_number = 2.71828f;
+    std::cout << "Another number: " << another_number << "\n";
+    // Now, we want to explicitly cast this to an integer.
+    int explicit_casted_number = static_cast<int>(another_number);
+    std::cout << "Casted number: " << explicit_casted_number << "\n";
+    // The output will be 2, because we explicitly told the compiler to convert it to an integer.
+    // Here, we used static_cast to perform the explicit casting.
+
+    // We can do this with C-style casting as well.
+    int c_style_casted_number = (int)another_number;
+    std::cout << "C-style casted number: " << c_style_casted_number << "\n";
+    // The output will still be 2, as we are explicitly converting the float to an integer.
+    // There are others like dynamic_cast, const_cast, and reinterpret_cast, but they are used for more specific purposes.
+
+    // Lets do another one with a string.
+    std::string str = "123";
+    std::cout << "String: " << str << "\n";
+    // Now, we want to convert this string to an integer.
+    int string_to_int = static_cast<int>(std::stoi(str));
+    std::cout << "Integer: " << string_to_int << "\n";
+    // The output will be 123, as we converted the string "123" to an integer.
+    // Just to meet your curiousity, stoi simply means "s(string) to i(integer).
+    // It's a function that comes with the "string" library we added at the top.
+
+    // Lets try with "67.345"
+    std::string str_float = "67.345";
+    std::cout << "String of a floating number: " << str_float << "\n";
+    // Now, we want to convert this string to a float.
+    float string_to_float = static_cast<float>(std::stof(str_float));
+    std::cout << "Floating type value of that string: " << string_to_float << "\n";
+    // The output will be 67.345, as we converted the string "67.345" to a float.
+
+    // Fun fact.
+    // Try with a string that contains characters, like "677ndc".
+    // To do that, we will need a second argument.
+    std::string str_with_chars = "677ndc";
+    std::cout << "String with characters: " << str_with_chars << "\n";
+    // Now, we want to convert this string to an integer.
+    size_t pos;
+    int string_with_chars_to_int = static_cast<int>(std::stoi(str_with_chars, &pos));
+    std::cout << "Integer of that string: " << string_with_chars_to_int << "\n";
+    // The otput will be 677. and the value of pos will be 3, which means it stopped converting at the first non-numeric character.
+    std::cout << "Position of first non-numeric character: " << pos << "\n";
+
+    // Note: size_t is an unsigned integer type that is used to represent the size of any object in bytes.
+
+    return 0;
+}