C Programming Week 2

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Questions and Answers

Which of the following is NOT a basic data type in C?

double

const (correct)

float

char

What is the primary characteristic of a pointer in C?

It holds the memory address of another variable. (correct)

It is used exclusively for string data.

It stores the value of variables directly.

It automatically manages memory allocation.

What is the typical size of an 'int' data type in C?

2 bytes

8 bytes

16 bytes

4 bytes (correct)

Which data type allows multiple members to share the same memory location?

Union Signup and view all the answers

Which of the following correctly defines a double data type variable?

double area = 50.0; Signup and view all the answers

How does the `const` keyword affect a variable in C?

It prevents the variable's value from being changed after initialization. Signup and view all the answers

What does the keyword 'void' signify in a function's return type?

The function does not return any value. Signup and view all the answers

Which statement about arrays in C is accurate?

The size of an array is fixed after definition. Signup and view all the answers

Which statement about local variables is true?

They are accessible only within the block they are declared. Signup and view all the answers

Which of the following describes derived data types?

They include types like arrays, pointers, and structures. Signup and view all the answers

What is the maximum size for a 'short' data type typically in C?

2 bytes Signup and view all the answers

What is the purpose of the `#define` directive in C?

To define macros or constants at the preprocessing stage. Signup and view all the answers

What is the purpose of the 'const' keyword in variable declaration?

To declare a variable that cannot be modified. Signup and view all the answers

What is a key requirement of the members of a structure in C?

They can be of different data types. Signup and view all the answers

Which of the following statements about signed and unsigned types is true?

Signed types can hold both negative and positive values, while unsigned types can only hold non-negative values. Signup and view all the answers

Which data type would be appropriate for storing the height of a person in meters?

double Signup and view all the answers

What is the main difference between variable definition and declaration?

Definition allocates memory, while declaration does not. Signup and view all the answers

What is the scope of a global variable in a C program?

Visible throughout the entire translation unit. Signup and view all the answers

How are variables declared in C?

With a data type and an optional initialization. Signup and view all the answers

Which of the following pairs of identifiers would be treated as different by C due to case sensitivity?

number and Number Signup and view all the answers

Which data type would be best for storing a single character?

char Signup and view all the answers

What is the lifetime of a local variable?

Only during the execution of the function or block. Signup and view all the answers

What must the main function return at the end of program execution?

an integer Signup and view all the answers

Which of the following correctly describes the purpose of 'int argc' in the main function?

Represents the number of command-line arguments Signup and view all the answers

What does the escape sequence '\n' do in a C program?

Moves the cursor to a new line Signup and view all the answers

What is the correct syntax to declare a main function that accepts command-line arguments?

int main(int argc, char* argv[]) Signup and view all the answers

Which comment style allows for multiple lines in C code?

/* This is a comment */ Signup and view all the answers

What will be the output of the following code: printf("Welcome\nto\nFallTerm!\n");?

Welcome to FallTerm! Signup and view all the answers

What is the role of the backslash '' in escape sequences?

It acts as an escape character Signup and view all the answers

Which of the following is NOT a valid escape sequence?

\p Signup and view all the answers

What does the declaration of a variable in C specify?

The type of the variable without allocating memory. Signup and view all the answers

Which of the following correctly describes the scope of global variables?

They exist for the entire program's execution time. Signup and view all the answers

When a local variable is created, when is its memory allocated?

When the function or block is entered. Signup and view all the answers

What is the primary distinction between variable definition and declaration in C?

Definition allocates memory; declaration specifies type and indicates implementation elsewhere. Signup and view all the answers

Which of the following types of variables is accessible throughout the entire program?

Global variables. Signup and view all the answers

What happens to the lifetime of a local variable once the function it belongs to exits?

The variable's memory is deallocated. Signup and view all the answers

What is the purpose of specifying a data type when declaring a variable in C?

To indicate how much memory to allocate for the variable. Signup and view all the answers

How does case sensitivity in C affect variable identifiers?

It allows different usage of similar names with differing cases to represent different variables. Signup and view all the answers

What does the variable 'institutionID' represent in the example provided?

A global variable that can be accessed in any function Signup and view all the answers

Which statement correctly describes 'studentID' in the resizeClass function?

It is a local variable that exists only within the while loop. Signup and view all the answers

What is the significance of data types in C programming?

They dictate the memory allocation and operations allowed on a variable. Signup and view all the answers

In C, how many bytes does a float typically occupy?

4 bytes (32 bits) Signup and view all the answers

Which data type is used to represent real numbers with greater precision in C?

double Signup and view all the answers

What does the keyword 'void' indicate when used in a function declaration?

The function does not return any value. Signup and view all the answers

Which of the following statements about local variables is incorrect?

They can be accessed outside of their defining function or block. Signup and view all the answers

Which statement about basic data types is true regarding their size?

A float generally occupies less memory than a double. Signup and view all the answers

What is the default precision for the %f format specifier in the printf function?

6 decimal places Signup and view all the answers

What would be the output of the following printf function: printf("x=%4.1f, y=%7.2f", 15.231, 65.875948);?

x=15.2, y=65.88 Signup and view all the answers

In the example with scanf("%3f%4f", &a, &b), what value will be stored in variable 'a' if the input is 5.965.87?

5.9 Signup and view all the answers

What determines the output's right justification in printf when using field width?

The specified field width Signup and view all the answers

How many characters will the output 'b' have if it is formatted using printf with a field width of 4 (e.g., b=5)?

4 characters Signup and view all the answers

Which of the following printf format specifiers correctly formats a floating-point number to display one digit after the decimal point and minimum width of 4?

%4.1f Signup and view all the answers

If the scanf function scans the input string '1234.56', what value will be assigned to 'b' when using scanf("%3f%4f", &a, &b)?

4.56 Signup and view all the answers

Which aspect of control flow in C does not involve looping?

Conditionals Signup and view all the answers

What is the primary characteristic of a struct in C?

Groups variables of different types in a single unit Signup and view all the answers

What does the 'long long' data type guarantee in C?

At least 8 bytes of storage Signup and view all the answers

Which of the following statements about pointers is accurate?

They can point to any data type Signup and view all the answers

What is a characteristic feature of a union in C?

Only one member can be accessed at a time Signup and view all the answers

What is the effect of using the 'const' keyword in a declaration?

It defines a variable that cannot be altered after initialization Signup and view all the answers

How are array sizes determined in C?

By the number of elements and the size of each element Signup and view all the answers

What type of variable can a pointer in C hold?

Addresses of any variable type Signup and view all the answers

What is the result of using the '#define' directive incorrectly, as in '#define MAX 10;' with a semicolon?

It generates an error during the compilation process. Signup and view all the answers

What does the 'scanf' function require to store input values in the variables specified?

The address of each variable involved. Signup and view all the answers

What will be the value of the variable 'term' after executing 'scanf("%d:%f", &marks, &term);' with the input '1500:20.5'?

20.5 Signup and view all the answers

How are macros defined with arguments expanded in C?

They replace arguments with passed values during compilation. Signup and view all the answers

What value will 'a' and 'b' hold after executing 'scanf("%2d%3d", &a, &b);' with input '6903901'?

a = 69, b = 39 Signup and view all the answers

Which of the following statements is true regarding the usage of the 'const' keyword?

Using 'const' improves code readability, indicating values should remain constant. Signup and view all the answers

What is the result of evaluating the macro 'SUM(4, 5)' using the definition '#define SUM(x, y) ((x) + (y))'?

It results in 9. Signup and view all the answers

What will the statement 'printf("Max students: %d\n", MAX_STUDENTS);' output given 'MAX_STUDENTS' is defined as 500?

Max students: 500 Signup and view all the answers

Study Notes

Course Information

Course Title: C Programming
Course Code: CST8234
Week: 2
Topic: Basics of the language

Objectives

Write simple C programs
Use I/O statements
Understand fundamental data types
Write simple decision-making statements
Learn about control specifiers
Understand macros
Introduction to arrays

Basics of the C Language

The main function is the entry point of a C program.
Using other files and libraries (e.g., #include <stdio.h>).
C program structure: preprocessor directives, function definitions, statements and expressions.
Variables
Control Flow (conditionals and loops)
Functions

Typical C Program Structure

Preprocessor directives: lines beginning with # (e.g., #include).
Function definitions: including the main function and other functions.
Statements and expressions: actual code to perform operations.

Example of a Typical C Program

#include <stdio.h>
int add(int a, int b) {
  return a + b;
}
int main() {
  int result = add(5, 3);
  printf("The result is %d\n", result);
  return 0;
}

#include Directive

Used to include the contents of a file within another file.
Useful for including libraries (e.g., stdio.h) and user-defined header files.
Syntax:
- #include <filename.h>: include from a standard library.
- #include "filename.h": include from a local directory.

How #include Works

Preprocessor stage: replaces the #include directive with the contents of the specified file before compilation.
Inclusion of content: the compiler processes included content as part of the original file.

Avoiding Multiple Inclusions

Use include guards (e.g., #ifndef, #define, #endif) to prevent multiple inclusions of the same header file.

The `main` Function (Example)

#include <stdio.h>
int main() {
  printf("Welcome to C!\n");
  return 0;
}

Variables

Variables in C store data.
They must be declared before use with a data type.
Example: int age = 25;, char initial = 'A';.
Different data types: int, char, float, double.

Variables Definition vs Declaration

Definition: allocates memory and initializes a variable.
Declaration: declares a variable without allocating memory.

Scope and Lifetime of Variables

Global variables: accessible throughout the entire program.
Local variables: accessible only within the function or block where they are declared.

Data Types

int: whole numbers
char: single characters
float: single-precision floating-point numbers
double: double-precision floating-point numbers

Derived Data Types

void: absence of type
array: collection of elements of the same type.
pointer: holds memory address of another variable.
struct: groups variables of different types.
union: similar to structure, but members share memory.

Modified Data Types

signed/unsigned int: specify whether integers can be negative or not.
short/long int: modify integer size.
long long: an extended version of long int.

const Keyword

const variables have values that cannot be changed after initialization.
Useful for defining constants (e.g., configuration parameters).

Macro

Used to define macros or constants during the preprocessing stage.
The #define directive is used to substitute text in the code with a literal value.
Example: macro #define MAX_VALUE 100.

`const` vs `#define`

const: has type safety, allocates memory.
#define: no type safety, no memory allocation.

Control Specifiers in `scanf` and `printf`

scanf reads input from the user, printf displays output.
Control strings specify input/output formats.
Use format specifiers (e.g., %d for integers, %f for floats, %s for strings).

Functions

Functions are fundamental building blocks in a C program.
Function syntax: <return type> <function name>(<parameters>).
Functions are reusable code blocks.

For Loop:

Used for fixed iterations

While Loop:

- Used for iterations based on a condition

Do-while:

 - The loop body is executed at least once.

Logical Operators

&&: logical AND, ||: logical OR, !: logical NOT

Relational Operators

- `==`, `!=`, `<`, `>`, `<=`, `>=`: Used to compare values and create conditions.

Ternary Operator

A shorthand for if-else statements.

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Description

This quiz covers the fundamentals of C programming language, focusing on writing simple C programs, understanding I/O statements, and fundamental data types. It also introduces control flow and arrays, providing essential skills for coding in C. Test your knowledge on these basic concepts with this quiz.