Exercise Questions - L-04: Operators, Precedence, Conditionals, Loops #

Operator Precedence #

Question 1: Precedence Prediction #

Predict the output of the following expressions without using a compiler:

#include <stdio.h>
int main() {
    int a = 10, b = 20, c = 3;
    printf("%d\n", a + b * c);           // Expression 1
    printf("%d\n", a * b / c + a);       // Expression 2
    printf("%d\n", a + b % c * a);       // Expression 3
    printf("%d\n", (a + b) * c % a);     // Expression 4
    return 0;
}

Question 2: Complex Expression Evaluation #

Given the following code, trace through the execution step by step:

int x = 5, y = 10, z = 2;
int result = x + y * z / x + y % z;

What is the final value of result? Show your work using operator precedence rules.

Question 3: Mixed Operators Challenge #

Evaluate these expressions manually, then write a C program to verify:

int a = 12, b = 4, c = 3;
printf("%d\n", a / b + c * a % b);
printf("%d\n", a + b * c / a - b);
printf("%d\n", (a + b) % c + a / b);

Enhanced Conditionals #

Question 4: Grade Calculator Enhancement #

Improve the grade calculation program from the lecture materials:

Add input validation (marks should be between 0-100)
Add grade point calculation (A=4.0, B=3.0, C=2.0, D=1.0, F=0.0)
Display both letter grade and grade point
Handle edge cases gracefully

Question 5: Multi-Condition Age Classifier #

Write a C program that classifies a person based on age and additional criteria:

Child (0-12): Check if school age (6+)
Teenager (13-19): Check if eligible for driving (16+)
Adult (20-64): Check if senior adult (50+)
Senior (65+): Check if super senior (80+)
Handle invalid ages

Question 6: Number Properties Analyzer #

Write a C program that takes an integer and determines:

Whether it’s positive, negative, or zero
If positive, whether it’s even or odd
If it’s a single digit, double digit, or multi-digit number
Whether it’s divisible by both 3 and 5

Switch Case Applications #

Question 7: Enhanced Calculator #

Create a calculator using switch case that:

Displays a menu of operations (+, -, *, /, %, ^)
Takes two numbers and an operator choice
Performs the calculation using switch case
Handles division by zero
Includes power operation (^ for exponentiation)

Question 8: Day of Week Calculator #

Write a C program using switch case that:

Takes a number (1-7) representing day of week
Displays the day name
Also displays whether it’s a weekday or weekend
Shows the next day
Handles invalid input

Create a menu-driven program using switch case:

1. Calculate area of circle
2. Calculate area of rectangle  
3. Calculate area of triangle
4. Exit

Each option should perform the respective calculation
Use appropriate formulas and handle invalid inputs
Loop back to menu after each operation until user chooses exit

While Loops #

Question 10: Number Pattern Generator #

Write programs using while loops to generate these patterns:

Pattern A:

Pattern B:

*
**
***
****
*****

Pattern C:

Question 11: Fibonacci Sequence Enhanced #

Based on the Fibonacci program from lecture, create an enhanced version that:

Takes n as input from user
Prints first n Fibonacci numbers
Also calculates and displays the sum of first n Fibonacci numbers
Handles the case when n <= 0
Shows the ratio of consecutive Fibonacci numbers

Question 12: Digital Root Calculator #

Write a C program that calculates the digital root of a number:

Digital root is obtained by repeatedly summing digits until single digit
Example: 9875 → 9+8+7+5 = 29 → 2+9 = 11 → 1+1 = 2
Use a while loop for the repeated summing process

Mathematical Algorithms #

Question 13: Euclid’s GCD Implementation #

Implement Euclid’s GCD algorithm as mentioned in the lecture:

Take two positive integers as input
Use the subtraction method: GCD(a,b) = GCD(a-b,b) if a>b
Continue until both numbers are equal
Display step-by-step process
Also implement the modulo version: GCD(a,b) = GCD(b, a%b)

Question 14: Factorial Calculator #

Write a C program to calculate factorial using while loop:

Take a non-negative integer as input
Calculate factorial using while loop
Handle special cases (0! = 1)
Display the calculation process
Check for overflow and display appropriate message

Question 15: Prime Number Checker #

Write a C program that:

Takes a positive integer as input
Checks if it’s prime using a while loop
Displays all factors if not prime
Shows the process of checking divisibility

Advanced Loop Problems #

Question 16: Perfect Number Finder #

Write a C program to check if a number is perfect:

A perfect number equals the sum of its proper divisors
Example: 6 = 1 + 2 + 3 (proper divisors of 6)
Find and display all proper divisors
Determine if the number is perfect, abundant, or deficient

Question 17: Armstrong Number Checker #

Create a program that checks if a number is an Armstrong number:

Armstrong number: sum of cubes of digits equals the number
Example: 153 = 1³ + 5³ + 3³ = 1 + 125 + 27 = 153
Handle numbers with different digit counts
Display the calculation process

Question 18: Number Reversal and Palindrome #

Write a C program that:

Takes an integer as input
Reverses the number using a while loop
Checks if the original number is a palindrome
Displays both original and reversed numbers

Loop Control and Nested Structures #

Question 19: Multiplication Table Generator #

Create a program that:

Takes a number n as input
Displays multiplication table for n (1 to 12)
Uses proper formatting for output
Asks if user wants another table
Continues until user chooses to exit

Question 20: Sum of Series Calculator #

Write programs to calculate these series using while loops:

Series A: 1 + 2 + 3 + … + n

Series B: 1² + 2² + 3² + … + n²

Series C: 1/1 + 1/2 + 1/3 + … + 1/n

Series D: 1! + 2! + 3! + … + n!

Debugging and Code Analysis #

Question 21: Debug the Loops #

Find and fix errors in these code snippets:

Code A:

#include <stdio.h>
int main() {
    int i = 1;
    while (i <= 10) {
        printf("%d\n", i);
        // Missing increment
    }
    return 0;
}

Code B:

#include <stdio.h>
int main() {
    int n = 5;
    int factorial = 0;  // Wrong initialization
    while (n > 0) {
        factorial *= n;
        n--;
    }
    printf("%d\n", factorial);
    return 0;
}

Question 22: Code Optimization #

Optimize the following code for better performance and readability:

#include <stdio.h>
int main() {
    int num = 100;
    int i = 2;
    int isPrime = 1;
    while (i < num) {  // Inefficient condition
        if (num % i == 0) {
            isPrime = 0;
        }
        i++;
    }
    if (isPrime == 1)
        printf("Prime\n");
    else
        printf("Not Prime\n");
    return 0;
}

Challenge Problems #

Question 23: Number Guessing Game #

Create a number guessing game:

Program generates a random number between 1-100
User has maximum 7 attempts to guess
Provide hints: “too high” or “too low”
Display number of attempts used
Ask if user wants to play again

Question 24: Simple Banking System #

Create a simple banking menu system:

1. Check Balance
2. Deposit Money
3. Withdraw Money
4. Display Transaction History
5. Exit

Use switch case for menu handling
Use loops for continuous operation
Validate all inputs (no negative amounts, sufficient balance for withdrawal)
Keep track of transaction count

Question 25: Pattern Generator Advanced #

Create a program that generates this diamond pattern:

    *
   ***
  *****
 *******
*********
 *******
  *****
   ***
    *

Take the size as input from user
Use nested loops efficiently
Handle both upper and lower parts of diamond

Integration Exercises #

Question 26: Comprehensive Number Analyzer #

Write a program that takes an integer and provides complete analysis:

Basic properties (even/odd, positive/negative)
Number of digits
Sum of digits and digital root
Reverse of the number
Check if palindrome
Check if prime
Check if perfect square
List all factors

Create a menu-driven program for mathematical series:

1. Fibonacci Series
2. Prime Numbers up to n
3. Factorial Series
4. Armstrong Numbers up to n
5. Perfect Numbers up to n
6. Exit

Use appropriate loops and conditionals for each option.

Code Quality and Best Practices #

Question 28: Code Documentation #

Add comprehensive comments to this Fibonacci code:

#include <stdio.h>
int main() {
    int n = 10;
    int i = 1;
    long long c = 0, f = 0, t = 1;
    while (i < n) {
        c = f + t;
        f = t;
        t = c;
        i = i + 1;
        printf("%lld\n", c);
    }
    return 0;
}

Question 29: Input Validation Framework #

Create a robust input validation system:

Function to validate integer input (within range)
Function to validate positive numbers
Function to handle invalid character input
Apply this to any previous exercise

Question 30: Performance Comparison #

Compare the efficiency of different approaches:

Calculate factorial using while loop vs for loop
Find prime numbers using different algorithms
Measure and discuss the differences in approach