FreeNotes
Dynamic memory allocation allows programs to allocate memory at runtime, enabling flexibility in managing memory. This is achieved through functions like malloc(), calloc(), and free(). malloc(): The malloc() function allocates a block of memory of a specified size and returns a pointer to it. The memory is not initialized. int *ptr = (int *)malloc(5 * … Read more
In C, = is the assignment operator, used to assign a value to a variable. For example, x = 5; assigns the value 5 to the variable x. On the other hand, == is the equality operator, used to compare two values for equality. It returns true (1) if the values are equal, and false … Read more
A switch statement is a control flow mechanism in C used to execute one of many code blocks based on the value of a variable. It evaluates an expression and compares its value with multiple case labels. When a match is found, the corresponding block of code is executed. The break statement is used to … Read more
In C, storage classes define the scope, lifetime, and visibility of variables. The main types are: auto: Default for local variables, their scope is limited to the block in which they are declared. register: Used for variables that should be stored in a register rather than RAM for faster access. static: Preserves the value of … Read more
Both while and do-while are used for repeating a block of code, but they differ in how they check the loop condition. In a while loop, the condition is checked before the code block is executed, meaning the loop may not execute at all if the condition is false initially. In contrast, a do-while loop … Read more
A pointer in C is a variable that stores the memory address of another variable. Instead of holding data itself, a pointer holds the location where the data is stored in memory. Pointers are used to directly access and modify the value of variables through their addresses. To declare a pointer, the asterisk (*) symbol … Read more
Header files in C contain declarations for functions, macros, constants, and variables that are used across multiple source files. They help in separating the interface of a program from its implementation. By including header files using the #include directive, programmers can ensure that the necessary declarations are available in each file that uses the functions … Read more
Comments are used in programs to add explanatory notes, descriptions, or reminders within the code. They are ignored by the compiler or interpreter and do not affect the execution of the program. Comments improve code readability, help document the logic, and provide clarity for future developers or collaborators. They are also useful for debugging and … Read more
Reserved words (also called keywords) are predefined words in programming languages that have a special meaning and are used for specific programming constructs, such as control flow, data types, or operations. Examples include if, for, int, and return in C. These words are reserved by the language and cannot be used as variable names because … Read more
area: Valid, as it is an identifier and doesn’t contain any illegal characters or reserved words. 5x: Invalid, as variables cannot start with a number. Sum: Valid, as it follows all rules for variable names. net pay: Invalid, as spaces are not allowed in variable names. float: Invalid, as float is a reserved keyword in … Read more