Learn C: Variables and Operators

                                
// Valid variable names
int age;
float _price;
int total1;

// Invalid variable names
int 1stNumber;
float double;

                              

                                
// Declaring variables with different data types
int count = 10;
float price = 9.99;
double balance = 1000.50;
char grade = 'A';

                              

                                
// Initializing a variable at declaration
int age = 25;

// Assigning a value to a variable later
int age;
age = 25;

                              

                                
// Explicit conversion (casting)
float price = 9.99;
int roundedPrice = (int)price; // roundedPrice will be 9

// Implicit conversion
int number = 10;
float decimal = number; // decimal will be 10.0

                              

                                
// Basic math operations
int sum = 5 + 3;       // Addition
int difference = 5 - 3; // Subtraction
int product = 5 * 3;    // Multiplication
int quotient = 5 / 3;   // Division

                              

                                
// Shorthand operators
int x = 10;
x += 5; // Equivalent to x = x + 5;
x *= 2; // Equivalent to x = x * 2;

                              

                                
// Comparison operators
int a = 5;
int b = 10;

bool isEqual = (a == b); // false
bool isGreater = (a > b); // false
bool isLess = (a < b); // true

                              

                                
// Logical operators
bool result1 = (5 > 3) && (8 < 10); // true (both conditions are true)
bool result2 = (5 > 3) || (8 > 10); // true (one condition is true)
bool result3 = !(5 > 3); // false (negation of the condition)