C Language Fundamentals Quiz

C Language Overview

The C programming language is a high-level general-purpose programming language developed by Dennis Ritchie between 1969 and 1973 while working at Bell Labs. It has since become one of the most influential languages in history due to its simplicity, efficiency, and flexibility. In this article, we'll explore some fundamental aspects of the C language, specifically its data types, arrays, memory management, functions, and pointers.

Data Types

In C, there are several standard data types available for declaring variables. These can broadly be classified into two categories: integer types and floating point types. Integer types consist of char, short int (or just short), int, long, and long long. Floating point types comprise float, double, and long double. Additionally, there is also a type called void. This type is used when you don't want to specify any particular return type for a function, such as in function prototypes.

Characters

Characters are declared using the char keyword followed by either a single character enclosed within quotes or an ASCII escape sequence. For instance, 'a', '\n', and '\t' represent the characters 'a', newline, and tab respectively. When dealing with Unicode characters, the equivalent escape sequences start with \u{...} where ... represents a four digit hexadecimal value representing the Unicode codepoint for that charachter. For example, '\u{2122}' would represent the copyright symbol ©.

Arrays

Arrays in C are collections of elements stored contiguously in memory, all having the same type, which must be specified during declaration. They are often defined using square brackets after their name, like so: type array_name[] = {..., ...}. By default, they have zero length, meaning they contain no elements until initialized. If the size is omitted, a compile time error will result if it is used without initializing them first.

Memory Management

Managing memory in C relies heavily on manual control over heap allocation and deallocation. Programmers need to allocate memory dynamically using the malloc() function from the standard library, providing the number of bytes required. Once done, this allocated block of memory needs to be manually freed up using free(ptr). Failure to do this results in a memory leak, which is a common cause of bugs in programs written in C.

Functions

A function in C allows you to group a set of statements together under a unique name, allowing reuse throughout your program. Declarations of functions typically take several forms depending on whether you intend to assign the value returned by calling the function to another variable or simply call the function directly.

// Function declaration with void return type
void myFunc();   // Prototype
myFunc();        // Calling function

// Function definition with int return type,
// stored in a variable named res
int myFunc(){
    int res;
    // ... Function body here
    return res;
};
myVar = myFunc();

Pointers

Pointers in C allow us to hold the address of a variable, rather than the actual value itself. They are created by prefixing a variable or constant with the ampersand (&) operator. These addresses can later be stored in other variables of pointer type and dereferenced using the asterisk (*) operator:

int main(){
    int i = 10;
    int *p = &i;      // p points to i - Holding an address
    printf("%d", *p); // Prints 10
    
    *p = 20;          // Deferences p and assignes new value to original varible
    printf("%d", i);  // Also prints 20

    return 0;
}

By understanding these core concepts — data types, arrays, memory management, functions, and pointers — you are well equipped to begin writing effective C programs.