C Programming Basics Quiz

C Programming Language Characteristics

• C is a structured programming language, allowing code organization and modularity.
• It is a procedural language, focusing on steps and algorithms.
• C supports various data types, including integers, floats, characters, and arrays.
• The language is portable, meaning it can be run on different platforms.
• C offers a wide range of operators, including arithmetic, relational, logical, and bitwise.
• C is a powerful and versatile language with a rich set of built-in functions and libraries.

Structure of a C Program

• A C program typically consists of a set of functions, including a main function that serves as the program's entry point.
• Functions are blocks of code that perform specific tasks.
• Comments are used to explain code and are ignored by the compiler.
• Preprocessing directives, starting with # (e.g., #include <stdio.h>) include headers and configure the compiler.
• Variable declarations define the data types and names of variables used in the program.
• Statements are instructions executed by the program in sequential order.
• The return statement is used to return a value from a function.

Constants in C

• Constants are fixed values that cannot be changed during program execution.
• Integer constants: Whole numbers (e.g., 10, -5, 0).
• Floating-point constants: Numbers with decimal points (e.g., 3.14, -2.5).
• Character constants: Single characters enclosed in single quotes (e.g., 'A', '%').
• String constants: Sequences of characters enclosed in double quotes (e.g., "Hello").

Tokens in C

• Tokens are the basic building blocks of a C program, recognized by the compiler.
• Example of each:
  • Keywords: if, else, for, while
  • Identifiers: name, age, sum
  • Constants: 100, 3.14, 'a', "Hello"
  • Operators: +, -, *, /, %, <, >, ==, !=
  • Special Symbols: {, }, (, ), ;, #

Keywords and Identifiers

• Keywords: Reserved words with special meaning in the C compiler.
• Identifiers: User-defined names for variables, functions, arrays, etc.
• Key Differences:
  • Purpose: Keywords have predefined roles, while identifiers are user-created for specific entities.
  • Case-sensitivity: Keywords are often case-insensitive, while identifiers may be case-sensitive depending on your compiler.

Data Types in C

• Data types define the kind of data a variable can hold and the operations it can perform.
• Basic Data Types:
  • int: for integers (whole numbers)
  • float: for floating-point numbers (numbers with decimal points)
  • char: for single characters
  • double: for larger floating-point numbers with higher precision
• Derived Data Types:
  • Arrays: Collections of elements of the same data type.
  • Structures: User-defined data types that group variables of different types.
  • Unions: Memory spaces that can hold different data types at different times.
  • Pointers: Variables that store memory addresses.

Naming Conventions for Variables

• Start with a Letter or underscore: counter, _radius
• Use Alphanumeric Characters: total_cost, score_1
• Case-Sensitive: totalCost is different from totalcost
• No Spaces or Special Characters: Use underscores instead of spaces (e.g., balance_due).
• Descriptive Names: Choose names that clearly explain the variable's purpose.

Program Examples

• Ramesh's Gross Salary:

#include <stdio.h>

int main() {
    float basicSalary, dearnessAllowance, houseRentAllowance, grossSalary;

    printf("Enter Ramesh's basic salary: ");
    scanf("%f", &basicSalary);

    dearnessAllowance = 0.40 * basicSalary;
    houseRentAllowance = 0.20 * basicSalary;
    grossSalary = basicSalary + dearnessAllowance + houseRentAllowance;

    printf("Ramesh's gross salary is: %.2f\n", grossSalary);

    return 0;
}

• Distance Conversion:

#include <stdio.h>

int main() {
    int distanceKm, distanceMeters, distanceCentimeters, distanceInches, distanceFeet;

    printf("Enter the distance between two cities in kilometers: ");
    scanf("%d", &distanceKm);

    distanceMeters = distanceKm * 1000;
    distanceCentimeters = distanceMeters * 100;
    distanceInches = distanceCentimeters / 2.54 ;
    distanceFeet = distanceInches / 12;

    printf("Distance in meters: %d\n", distanceMeters);
    printf("Distance in centimeters: %d\n", distanceCentimeters);
    printf("Distance in inches: %d\n", distanceInches);
    printf("Distance in feet: %d\n", distanceFeet);

    return 0;
}

• Student Marks and Percentage:

#include <stdio.h>

int main() {
    int subject1, subject2, subject3, subject4, subject5, totalMarks, percentage;

    printf("Enter marks for subject 1: ");
    scanf("%d", &subject1);

    printf("Enter marks for subject 2: ");
    scanf("%d", &subject2);

    printf("Enter marks for subject 3: ");
    scanf("%d", &subject3);

    printf("Enter marks for subject 4: ");
    scanf("%d", &subject4);

    printf("Enter marks for subject 5: ");
    scanf("%d", &subject5);

    totalMarks = subject1 + subject2 + subject3 + subject4 + subject5;
    percentage = (totalMarks * 100) / 500;

    printf("Total Marks: %d\n", totalMarks);
    printf("Percentage: %d%%\n", percentage);

    return 0;
}

• Fahrenheit to Centigrade Conversion:

#include <stdio.h>

int main() {
    float fahrenheit, centigrade;

    printf("Enter temperature in Fahrenheit: ");
    scanf("%f", &fahrenheit);

    centigrade = (fahrenheit - 32) * 5 / 9;

    printf("Temperature in Centigrade: %.2f\n", centigrade);

    return 0;
}

• Rectangle and Circle Calculations:

#include <stdio.h>

int main() {
    float length, breadth, radius, rectangleArea, rectanglePerimeter, circleArea, circleCircumference;

    printf("Enter length of the rectangle: ");
    scanf("%f", &length);

    printf("Enter breadth of the rectangle: ");
    scanf("%f", &breadth);

    printf("Enter radius of the circle: ");
    scanf("%f", &radius);

    rectangleArea = length * breadth;
    rectanglePerimeter = 2 * (length + breadth);
    circleArea = 3.14159 * radius * radius;
    circleCircumference = 2 * 3.14159 * radius;

    printf("Rectangle Area: %.2f\n", rectangleArea);
    printf("Rectangle Perimeter: %.2f\n", rectanglePerimeter);
    printf("Circle Area: %.2f\n", circleArea);
    printf("Circle Circumference: %.2f\n", circleCircumference);

    return 0;
}

• Swapping Two Numbers:

#include <stdio.h>

int main() {
    int c, d, temp;

    printf("Enter the value of C: ");
    scanf("%d", &c);

    printf("Enter the value of D: ");
    scanf("%d", &d);

    printf("Before swapping: C = %d, D = %d\n", c, d);

    temp = c;
    c = d;
    d = temp;

    printf("After swapping: C = %d, D = %d\n", c, d);

    return 0;
}

Branching and Looping in C

• Branching: Used to alter the program's execution flow based on conditions.
  • if statement: Executes a block of code if a condition is true.
  • else statement: Executes a different block of code if the if condition is false.
  • if-else if-else chain: Allows for multiple conditions to be evaluated.
• Looping: Repeats a block of code multiple times until a certain condition is met.
  • for loop: Executes a block of code a specific number of times.
  • while loop: Executes a block of code as long as a condition remains true.
  • do-while loop: Executes a block of code at least once, then checks a condition to continue looping.
• Switch Statement: Evaluates an expression against a set of constant integer values, and executes the corresponding code block.
• Goto Statement: Unconditionally jumps to a labeled statement within the same function, often avoided due to potential code complexity.
• Comma Operator: Evaluates multiple expressions, with the last expression's value being returned. Used to combine statements that may be executed independently.

Operator Precedence in Expression Evaluation:

• Operators have different priorities when evaluating expressions.
• The order of operations is used to determine which operations are performed first:
  • Parentheses: Expressions inside parentheses are evaluated first.
  • Unary operators: Operators acting on single operands (e.g., !, -) are evaluated next.
  • Multiplicative operators: *, /, %
  • Additive operators: +, -
  • Relational operators: ==, !=, <, >, <=, >=
  • Logical operators: &&, ||
  • Assignment operator: =

Prime Number Algorithm, Flowchart, and Code

• Algorithm:
  • Input an integer.
  • If the number is less than 2, it's not a prime number.
  • Iterate from 2 to the square root of the number.
  • Check if the number is divisible by any of these values.
  • If divisible, it's not a prime number; otherwise, it is.
• Flowchart: (To be visually drawn but can't be included here - would visually show the steps described in the algorithm).
• C Code:

#include <stdio.h>
#include <math.h>

int main() {
    int number, i, isPrime = 1; 

    printf("Enter a positive integer: ");
    scanf("%d", &number);

    if (number <= 1) {
        isPrime = 0; 
    } else {
        for (i = 2; i <= sqrt(number); i++) {
            if (number % i == 0) {
                isPrime = 0; 
                break; 
            }
        }
    }

    if (isPrime) {
        printf("%d is a prime number.\n", number);
    } else {
        printf("%d is not a prime number.\n", number);
    }

    return 0;
}

Continue Statement

• The continue statement is used to skip the current iteration of a loop without terminating the loop entirely.
• It jumps to the next iteration of the loop.

Switch Statement in C

• Syntax:

switch (expression) {
    case constant_value1: 
        // Code to be executed if expression matches constant_value1
        break;
    case constant_value2:
        // Code to be executed if expression matches constant_value2
        break;
    // ... more cases
    default:
        // Code to be executed if no case matches
}

• Example:

#include <stdio.h>

int main() {
    int day;

    printf("Enter a day of the week (1-7): ");
    scanf("%d", &day);

    switch (day) {
        case 1:
            printf("Monday\n");
            break;
        case 2:
            printf("Tuesday\n");
            break;
        case 3:
            printf("Wednesday\n");
            break;
        case 4:
            printf("Thursday\n");
            break;
        case 5:
            printf("Friday\n");
            break;
        case 6:
            printf("Saturday\n");
            break;
        case 7:
            printf("Sunday\n");
            break;
        default:
            printf("Invalid day number.\n");
    }

    return 0;
}

Loops and Their Types

• Loops are used to repeat blocks of code as long as a certain condition is met.
• For Loop: Repeats a block of code a specific number of times. It consists of three parts:
  • Initialization: Executes once before the loop starts (e.g., setting a loop counter).
  • Condition: Checked before each iteration. If true, the loop body executes; if false, the loop terminates.
  • Increment/Decrement: Executed after each iteration (e.g., updating the loop counter).
• While Loop: Keeps executing a block of code as long as a specified condition remains true. The condition is checked at the beginning of each iteration.
• Do-While Loop: Similar to a while loop, but the condition is checked at the end of each iteration. This ensures the loop body executes at least once.

Conditional Statements in C

• Conditional statements allow the program to make decisions based on conditions.
• If Statement: Executes a block of code if a specified condition is true.
  • Syntax:

  if (condition) {
      // Code to be executedif condition is true
  }
  

• Else Statement: Executes a block of code if the if statement's condition is false.
  • Syntax:

  if (condition) {
      // Code to be executed if condition is true
  } else {
      // Code to be executed if condition is false
  }  
  

• Else If Statement: Provides alternative conditions to be checked if previous if or else if conditions are false.
  • Syntax:

  if (condition1) {
      // Code for condition1
  } else if (condition2) {
      // Code for condition2
  } else if (condition3) {
      // Code for condition3
  } else {
      // Code for no matching condition
  }
  

Factorial Calculation using Recursion

• Recursion: A function calling itself within its own definition.
• Factorial: The product of all positive integers less than or equal to a given number.
  • Factorial of 5 (denoted as 5!) is 5 * 4 * 3 * 2 * 1 = 120.
• C Code:

#include <stdio.h>

int factorial(int n);

int main() {
    int number, result;

    printf("Enter a non-negative integer: ");
    scanf("%d", &number);

    if (number < 0) {
        printf("Factorial is not defined for negative numbers.\n");
    } else {
        result = factorial(number);
        printf("Factorial of %d is %d\n", number, result);
    }

    return 0;
}

int factorial(int n) {
    if (n == 0) {
        return 1;  // Base case for recursion
    } else {
        return n * factorial(n - 1);  // Recursive step
    }
}

Arrays in C

• Array: A collection of elements of the same data type, stored in contiguous memory locations.
• Initialization:
  • Direct initialization: Provide values directly during declaration (e.g., int numbers[5] = {1, 2, 3, 4, 5};)
  • Partial initialization: Provide some values, others are assigned to 0 (e.g., int ages[10] = {20, 25, 30};) The remaining elements get 0.
  • Indirect initialization: Assign values to elements individually after declaration (e.g., numbers[0] = 10; numbers[1] = 20;).

String Handling Functions in C

• String: A sequence of characters terminated by a null character (\0).

• Functions: (Five examples along with descriptions):

  • strcpy(destination, source): Copies a string from source to destination.
  • strcat(destination, source): Concatenates (joins) two strings.
  • strlen(string): Returns the length of a string (excluding the null terminator).
  • strcmp(string1, string2): Compares two strings lexicographically and returns an integer:
    • A negative value if string1 is alphabetically smaller than string2.
    • Zero if string1 and string2 are equal.
    • A positive value if string1 is alphabetically larger than string2.
  • strchr(string, character): Finds the first occurrence of a specified character in a string and returns a pointer to that character.