C Programming Concepts

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Questions and Answers

What is the output of the program that includes modifying the character in the string 'Hello' to 'M' using a pointer?

Mello (correct)

Hello

Mlllo

Mello!

What is the primary purpose of the `malloc()` function in C?

To free previously allocated memory.

To allocate a specified number of bytes of memory during runtime. (correct)

To compile a C program.

To pause the execution of a program.

In C programming, what distinguishes `break` from `continue` in control flow?

Both are used to exit a loop.

Break skips to the end of the loop, while continue restarts the loop.

Break exits the loop, while continue skips the rest of the current iteration. (correct)

Both are used to skip to the next iteration.

How would you describe global variables in C?

Variables that are accessible throughout the entire program. Signup and view all the answers

Which of the following statements about pointers is true?

Pointers can only hold the address of variables of the same data type. Signup and view all the answers

What will be the output of the following statement if `n = 5`: 1 + 1/2 + 1/3 + 1/4 + 1/5?

2.28333 Signup and view all the answers

Which function is typically used to read the elements of a matrix in C?

scanf() Signup and view all the answers

In C programming, how can you define a new data type using `typedef`?

By assigning a name to a previously defined data type. Signup and view all the answers

What will be the output of the following code snippet? `int main() { printf("%d", printf("%d", 1234)); return 0; }`

4 Signup and view all the answers

Which of the following are types of errors in programming?

Logical Error Signup and view all the answers

If `int a = 5, b = 7, c = 12, d = 15, x;` and the expression `x = + + a + + + b + + + c + + + d;` is evaluated, what is the value of `x`?

39 Signup and view all the answers

Given the code `scanf("%2d%5d", &a, &b);` where `a = 12345` and `b = 678`, what will be the output when printed as `printf("\n a = %d and b = %d", a, b);`?

a = 12 and b = 678 Signup and view all the answers

What will be the output of the code snippet `char arr[] = {"RVC", "BMSC", "MSRIT"}; printf("%s\n", arr);`?

RVC Signup and view all the answers

What is the output of the following code snippet? `struct student { }; void main() { struct student s; printf("%d", sizeof(s)); }`

1 Signup and view all the answers

Which built-in string functions are typically supported in C?

strlen() Signup and view all the answers

What will be the output of the following program? `#include <stdio.h> int main() { printf("Hello, World!\n"); return 0;}`

Hello, World! Signup and view all the answers

Study Notes

Output of `printf` Function

The output of the provided printf function is 12344
- printf("%d", printf("%d", 1234));
- The inner printf function prints 1234 and returns the number of characters printed, which is 4.
- The outer printf function then prints the returned value, 4, as an integer.

Types of Errors

Two types of errors that can occur in a program
- Syntax Errors: These errors arise from incorrect usage of syntax, such as missing semicolons, incorrect variable declarations, or invalid keywords.
- Runtime Errors: These errors occur during the program's execution due to issues like division by zero, accessing an array element beyond its bounds, or attempting to open a non-existent file.

Evaluation of Expression

Given the expression X = ++a + ++ + b + ++ + c + ++ + d; with initial values:
- a = 5
- b = 7
- c = 12
- d = 15
After the expression is evaluated, the values are:
- X = 43
- a = 6
- b = 9
- c = 14
- d = 17
The expression is evaluated from left to right.
The prefix increment operator ++ increments the variable before its value is used in the expression.

`scanf` Function Output

The provided scanf function reads values based on the specified format specifiers:
- scanf(“%2d%5d”, &a, &b);
- %2d reads the first two digits of a and assigns them to a.
- %5d reads the next five digits of b and assigns them to b.
Since the values are a = 12345 and b = 678:
- The output for printf(“\n a = %d and b = %d”, a, b); will be:
- a = 12 and b = 678

Built-in String Functions in C

Built-in string functions in C provide support for string manipulations, such as:
- strlen(string): Determines the length of a string.
- strcpy(target, source): Copies the source string to the target string.
- strcat(target, source): Concatenates the source string to the end of the target string.
- strcmp(string1, string2): Compares two strings lexicographically.
- strchr(string, character): Locates the first occurrence of a character in a string.
- strstr(string1, string2): Finds the first occurrence of a substring within a string.
- strtok(string, delimiter): Divides a string into tokens based on a delimiter.
- strlwr(string): Converts a string to lowercase.
- strupr(string): Converts a string to uppercase.

Output of the `printf` Function in the `char arr[]` Example

The program has an array of strings arr[].
The printf function is used to print the arr array two times.
Since the array contains only one string, it will be printed twice:
- The output of:
  - printf("%s\n", arr);
  - printf("%s\n", arr);
- will be \nRVCE\nRVCE

Size of Structure `student`

The output of the code will be 0 since the structure student is defined as an empty structure
- struct student {};
- The sizeof() operator returns the size of the given argument, which is an empty structure, its size is 0 in this case.

Output of the `printf` Function in the `char str` Example

The program has a character array str and a pointer p pointing to it.
When we try to modify the value pointed to by p using *p = ‘M’; the output will be Hello.
Trying to modify the character array by the pointer throws a warning in the compiler
The warning states that the character array str is not a modifiable lvalue.

`fseek` Function Purpose

The fseek function in C is used to set the position of the file pointer within a file.
It takes three arguments:
- The file pointer
- The offset to move the file pointer
- The origin from which to move the file pointer

Differences between `calloc` and `malloc` Functions

calloc and malloc both allocate memory dynamically from the heap.
The main differences between them are:
- Initialization: calloc initializes all the allocated memory to 0, while malloc does not.
- Argument: malloc accepts a single argument specifying the number of bytes to be allocated, whereas calloc takes two arguments specifying the number of blocks and size of each block in bytes.

Sum of Even Numbers Algorithm and Flowchart

Algorithm*
Input: The program takes the starting and ending integers as input.
Initialization: Initialize the sum variable to 0.
Iteration: Loop through each integer from the starting value to the ending value.
Even Check: For each integer, check if it is an even number.
Addition: If the integer is even, add it to the sum variable.
Output: Print the final sum of all the even numbers.
Flowchart*
The flowchart depicts the algorithm visually.
Start
Get the start and end integers
Initialize the sum variable to 0
Start the loop
Check if the current number is even
If the number is even then add it to the sum
Increment the counter
End loop
Print the sum
End

Compiling and Running a C Program

Compiling: The source code written in C needs to be translated into machine-readable code. This process is known as compilation.
Linking: The compiled code is then linked with other necessary libraries to create an executable file. Linking ensures that the program can access the resources and functions needed for execution.
Running: The executable file generated after the linking process can then be run on a computer.

C Program to Perform Operations on a Matrix

The program will allow the user to:
- Read elements of a matrix of size n x n.
- Compute the sum of the diagonal elements.
- Compute the sum of all elements.

Break and Continue Statements

Break: The break statement acts as a jump out of a loop and continues with the next statement after the loop.
Continue: The continue statement skips the current iteration of the loop and proceeds to the next iteration.

Program to Reverse an Integer

The program will take an integer as input and reverse its digits using a loop.
It will iterate through the digits of the integer, extracting each digit and adding it to a new reversed integer.

Program to Recognize Vowel or Consonant

The program will take a character as input and determine if it is a vowel or consonant.
It will use a switch statement to check if the character matches any of the vowels and display the appropriate output.

Program to Display the Harmonic Series

The program will take a positive integer n as input.
It will calculate the sum of the first n terms of the harmonic series.
The harmonic series is defined as 1 + 1/2 + 1/3 + 1/4 + 1/5 + ... + 1/n.

Program to Check for Palindrome

The program takes a string as input and checks if it is a palindrome using two functions:
- findLength: This function calculates the length of the string.
- checkPalindrome: This function checks if the string is a palindrome by comparing characters from the beginning and end of the string.

Global and Local Variables

Global Variables: Global variables are declared outside any function, making them accessible from anywhere within the program. They maintain their values throughout the program's execution.
Local Variables: Local variables are declared inside functions, with their scope limited to the function in which they are declared. Their values are not accessible outside the defining function.

Program to Sort Names

The program takes an array of names as input and sorts them using a custom sorting function.
The sorting function uses string comparison to arrange the names in lexicographical order.

Categories of C Functions

Standard Library Functions: These are built-in functions provided in the C library, such as printf(), scanf(), strlen(), strcpy(), and math functions (sqrt(), pow(), sin(), etc.)
User-Defined Functions: These are functions created by the programmer to perform specific tasks.
- They are defined with a return type, name, parameters, and function body, similar to the structure of a standard library function.

Arithmetic Operations with Pointers

Pointers can be used to perform arithmetic operations on memory addresses.
The basic arithmetic operations supported on pointers are:
- ++ (Increment): Increments the pointer address by the size of the data type being pointed to.
- -- (Decrement): Decrements the pointer address by the size of the data type being pointed to.
- + (Addition): Adds an offset to the pointer's address, effectively moving the pointer forward in memory.
- - (Subtraction): Subtracts an offset from the pointer's address, moving the pointer backward in memory.

`typedef` and Complex Numbers

typedef is used to create an alias or a nickname for an existing data type.
The code uses a structure (COMPLEX) to represent complex numbers, containing real and imaginary parts.
It defines a function AddCompNum to add two complex numbers by adding their real and imaginary parts.

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Description

This quiz covers key concepts in C programming, including the behavior of the printf function, types of program errors, and expression evaluation. Test your understanding of syntax errors, runtime errors, and how variables are manipulated during expressions in C.

C Programming Concepts

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Questions and Answers

What is the output of the program that includes modifying the character in the string 'Hello' to 'M' using a pointer?

What is the primary purpose of the malloc() function in C?

In C programming, what distinguishes break from continue in control flow?

How would you describe global variables in C?

Which of the following statements about pointers is true?

What will be the output of the following statement if n = 5: 1 + 1/2 + 1/3 + 1/4 + 1/5?

Which function is typically used to read the elements of a matrix in C?

In C programming, how can you define a new data type using typedef?

What will be the output of the following code snippet? int main() { printf("%d", printf("%d", 1234)); return 0; }

Which of the following are types of errors in programming?

If int a = 5, b = 7, c = 12, d = 15, x; and the expression x = + + a + + + b + + + c + + + d; is evaluated, what is the value of x?

Given the code scanf("%2d%5d", &a, &b); where a = 12345 and b = 678, what will be the output when printed as printf("\n a = %d and b = %d", a, b);?

What will be the output of the code snippet char arr[] = {"RVC", "BMSC", "MSRIT"}; printf("%s\n", arr);?

What is the output of the following code snippet? struct student { }; void main() { struct student s; printf("%d", sizeof(s)); }