Mastering Control Statements in C Programming: A Hands-on Guide with Basic Exercises

 

Mastering Control Statements in C Programming: A Hands-on Guide with Basic Exercises

Introduction

Control statements are the backbone of programming, allowing developers to dictate the flow of execution based on specific conditions. In this blog post, we’ll explore a variety of beginner and intermediate exercises focused on conditional control statements in C programming. Each exercise is accompanied by a code solution and a short explanation to help you understand and implement these concepts effectively.

Prerequisite 

To practice this project, ensure that you have Code::Blocks installed on your system. If not, you can download it from the official Code::Blocks Download Page.

Exercise 1: Check If a Number is Even or Odd

Question:

Write a program to check weather a number input through the keyboard is even or odd.

Code:

#include <stdio.h>

int main()
{
    int number;

    printf("---------------------------------------------------------");
    printf("\nThis program will test if the input number is even or odd");
    printf("\n---------------------------------------------------------");

    printf("\nInput an integer number: ");
    scanf("%d", &number);

    if(number % 2 == 0)
    {
        printf("\nThe number is Even.");
    }
    else
    {
        printf("\nThe number is Odd.");
    }
}
  

Explanation:

The code utilizes the modulo operator (%) to check for evenness. If the remainder after dividing the number by 2 is 0, the number is even; otherwise, it’s odd.

Sample Input/Output:

Exercise 1 Output

• Input: 15 
• Output: The number is Odd.
• Input: 24 (Try This)
• Output: The number is Even.

Exercise 2: Maximum Value of Two Numbers

Question:

Write a program to print the maximum out of two numbers.

Code:

#include <stdio.h>

int main()
{
    printf("\n-----------------------------------------------------------");
    printf("\nThis program will test the maximum out of two input numbers");
    printf("\n-----------------------------------------------------------");

    int number1, number2;
    printf("\nEnter two different integer number (space the number): ");
    scanf("%d%d", &number1, &number2);

    if(number1 >= number2)
    {
        printf("\nThe First number is the Maximum number");
    }
    else
    {
        printf("\nThe Second number is the maximum number");
    }
}

Explanation:

The code uses an if-else statement to compare the two numbers. If number1 is greater than or equal to number2, number1 is the maximum; otherwise, number2 is the maximum.

Sample Input/Output:

Exercise 2 Output

• Input: 10 5
• Output: The first number is the Maximum number.
• Input: 3 8 (Try This)
• Output: The second number is the maximum number

Exercise 3: Maximum Value of Three numbers

Question:

Write a program to print the maximum out of three numbers.

Code:

#include <stdio.h>

int main()
{
    printf("\n--------------------------------------------------------------");
    printf("\nThis program test the maximum number among 3 different numbers");
    printf("\n--------------------------------------------------------------");

    int number1, number2, number3;

    printf("\n\nInput 3 different integer numbers (space the numbers): ");
    scanf("%d%d%d", &number1, &number2, &number3);

    if(number1 >= number2 && number1 >= number3)
    {
        printf("\nThe First number is the maximum number.");
    }
    else if(number2 >= number1 && number2 >= number3)
    {
        printf("\nThe Second number is the maximum number.");
    }
    else
    {
        printf("\nThe third number is the maximum number.");
    }
}

Explanation:

The code employs nested if-else statements to compare the three numbers and determine the maximum.

Sample Input/Output:

Exercise 3 Output

• Input: 15 7 20
• Output: The third number is the maximum number.
• Input: 25 30 18
• Output: The second number is the maximum number.

Exercise 4: Maximum Value of Four Numbers

Question:

Write a program to print the maximum out of four numbers, using Nested-if-else and short-logic.

Code (Nested if-else):

#include <stdio.h>

int main()
{
    printf("\n----------------------------------------------------------------------");
    printf("\nThis program will test the maximum number among four different numbers");
    printf("\n----------------------------------------------------------------------");

    int number1, number2, number3, number4;
    printf("\n\nInput 4 different integer numbers (space the inputs): ");
    scanf("%d%d%d%d", &number1, &number2, &number3, &number4);

    if(number1 >= number2 && number1 >= number3 && number1 >= number4)
    {
        printf("\nThe first number is the maximum number\n");
    }
    else if(number2 >= number1 && number2 >= number3 && number2 >= number4)
    {
        printf("\nThe second number is the maximum number\n");
    }
    else if(number3 >= number1 && number3 >= number2 && number3 >= number4)
    {
        printf("\nThe third number is the maximum number\n");
    }
    else
    {
        printf("\nThe fourth number is the maximum number\n");
    }
}

Code (Short-logic):

#include <stdio.h>

int main()
{
    printf("\n----------------------------------------------------------------");
    printf("\nThis program will test four different number to know the maximum");
    printf("\n----------------------------------------------------------------");

    int num1, num2, num3, num4, maxi;

    printf("\n\nInput 4 different integer numbers (space the input): ");
    scanf("%d%d%d%d", &num1, &num2, &num3, &num4);

    maxi = num1;

    if(num2 > maxi)
    {
        maxi = num2;
    }
    if(num3 > maxi)
    {
        maxi = num3;
    }
    if(num4 > maxi)
    {
        maxi = num4;
    }
    printf("\nThe maximum number is %d\n", maxi);
}

Explanation:

• Nested if-else: Uses nested if-else statements to compare all four numbers.
• Short-logic: Uses a temporary variable (maxi) to store the maximum value found so far.

Sample Input/Output:

• Input: 10 25 8 15
• Output: The second number is the maximum number

Exercise 4 Output

Exercise 5: Second maximum of Three Numbers

Question:

Write a program to print the second maximum out of three numbers.

Code:

#include <stdio.h>

int main()
{
    printf("\n---------------------------------------------------------------");
    printf("\nThe program print out the second maximum number from the 3 inputs");
    printf("\n---------------------------------------------------------------");

    int num1, num2, num3, sec;

    printf("\n\nEnter 3 different integer numbers (space the inputs): ");
    scanf("%d%d%d", &num1, &num2, &num3);

    if((num1 > num2 && num1 < num3) || (num1 > num3 && num1 < num2))
    {
        sec = num1;
    }
    else if((num2 > num1 && num2 < num3) || (num2 > num3 && num2 < num3))
    {
        sec = num2;
    }
    else
    {
        sec = num3;
    }
    printf("\nThe second maximum number is %d\n", sec);
}

Explanation:

The code determines the second-largest number by checking if a number is greater than one number and less than another.

Sample Input/Output:

• Input: 10 20 15 
• Output: The second maximum number is 15

Exercise 5 Output

Exercise 6: Check for Leap Year

Question:

Write a program to check whether a year is leap year or not.

Code:

#include <stdio.h>

int main()
{
    printf("\n---------------------------------------------------------");
    printf("\nThis program will tell weather a year is leap year or not");
    printf("\n---------------------------------------------------------");

    int year;

    printf("\nInput the year: ");
    scanf("%d", &year);

    if((year % 4 == 0 && year % 100 != 0)|| (year % 400 == 0))
    {
        printf("\nThe year %d is a leap year\n", year);
    }
    else
    {
        printf("\nThe year %d is not a leap year\n", year);
    }
}

Explanation:

The code uses the following conditions to check for a leap year:

•  Divisible by 4. 
• Not divisible by 100.
• Or divisible by 400.

Sample Input/Output:

Exercise 6 Output

• Input: 2024
• Output: The year 2024 is a leap year
• Input: 1900
• Output: The year 1900 is not leap year.

Exercise 7: Calculate Student Grade

Question:

Write a program to calculate the grade of a student after the input of marks of that student, given the conditions that:

• 90 or above: Grade A
• 70-89: Grade B
• 50-69: Grade C
• Below 50: Grade F

Code:

#include <stdio.h>

int main()
{
    printf("\n----------------------------------------------------------------");
    printf("\nThis program will award the appropriate Grade to the test score.");
    printf("\n----------------------------------------------------------------");

    int score;
    printf("\n\nEnter the Test Score: ");
    scanf("%d", &score);

    if(score >= 90)
        printf("\nGrade: A");
    else if(score >= 70 && score <= 90)
        printf("\nGrade: B");
    else if(score >= 50 && score <= 70)
        printf("\nGrade: C");
    else
        printf("\nGrade: F");
}

Sample Input/output:

Exercise 7 Output

• Input: 85
• Output: Grade: B
• Input: 92 (Try This)
• Output: Grade: A

Exercise 8: Calculate Telephone Bill

Question:

Write a program to compute the telephone bill of a customer. Monthly Rental is 100 NGN. Rates are as follows:

• No of calls 1 to 100                           rate = 0
• No of calls 101 to 200                       rate = 0.80 NGN per call
• No of calls 201 to 500                       rate = 1.00 NGN per call
• No of calls 501 above                       rate = 1.20 NGN per call

Code:

#include <stdio.h>
int main()
{
    printf("\n-----------------------------------------------------------------------");
    printf("\nThis Program will compute the telephone bill of a customer in a month.");
    printf("\n-----------------------------------------------------------------------");

    int calls;
    printf("\nEnter the number of calls made in a month: ");
    scanf("%d", &calls);

    // Monthly rental is 100.0
    float bill = 0.00;
    if(calls >= 1 && calls <= 100)
    {
        bill = (0.00 * 100.00);
        printf("\nYour Telephone bill for the month is %.2f NGN\n", bill);
    }
    else if(calls >= 101 && calls <= 200)
    {
        bill = (0.80 * 100.00);
        printf("\nYour Telephone bill for the month is %.2f NGN\n", bill);
    }
    else if (calls >= 201 && calls <= 500)
    {
        bill = (1.00 * 100.00);
        printf("\nYour Telephone bill for the month is %.2f NGN\n", bill);
    }
    else
    {
        bill = (1.20 * 100.00);
        printf("\nYour Telephone bill for the month is %.2f NGN\n", bill);

    }
}

Sample Input/output:

• Input: 150
• Output: Your Telephone bill for the month is 80.00 NGN

Exercise 8 Output

Exercise 9: Computes Employee Pension

Question:

Write a program to compute the pension of an employees.

If the person is male:

• Age >= 90                   pension is 4000
• Age >= 60                   pension is 6000
• Age < 60                     pension is 0

If the person is female:

• Age >= 90                   pension is 3000
• Age >= 60                   pension is 5000
• Age < 60                     pension is 0

Code:

#include <stdio.h>

int main()
{
    printf("\n------------------------------------------------------------------");
    printf("\nThis program will compute the pension of male and female employee");
    printf("\n------------------------------------------------------------------");

    int sex;
    int age;
    printf("\nEnter the Employees' age: ");
    scanf("%d", &age);
    printf("\nWhat is the sex of the Employee?\n1 Male\n2 Female\n");
    scanf("%d", &sex);

    switch(sex)
    {
    case 1:
        {
            if(age >= 90)
                printf("\nEmployee Pension is 4000.00 NGN\n");
            else if(age >=60 && age <= 90)
                printf("\nEmployee Pension is 6000.00 NGN\n");
            else
                printf("\nEmployee Pension is 0.00 NGN\n");
            break;
        }
     case 2:
        {
            if(age >= 90)
                printf("\nEmployee Pension is 3000.00 NGN\n");
            else if(age >=60 && age <= 90)
                printf("\nEmployee Pension is 5000.00 NGN\n");
            else
                printf("\nEmployee Pension is 0.00 NGN\n");
            break;
        }
    }
    return (0);
}

Explanation:

• The code uses a switch-case statement to handle different genders.
• Nested if-else statements within each case determine the pension based on age.

Sample Input/Output:

Exercise 9 Output

• Input: Age 65, Sex: 1 (Male)
• Output: Employee pension is 6000.00 NGN

Exercise 10: Magic Number

Question:

Write a program to check weather a 3 digit number is a magic number or not. (Palindrome) A number is a magic number if its reverse is same as the original number.

Code:

#include <stdio.h>

int main()
{
    printf("\n-------------------------------");
    printf("\nCHECK IF YOUR NUMBER IS MAGIC");
    printf("\n-------------------------------");

    int number;
    printf("\nEnter a 3 digit number: ");
    scanf("%d", &number);

    if(number >=100 && number <= 999)
    {
        int magic = number;
        int rev_number = 0;
        int last_digit;

        last_digit = magic%10;
        rev_number = rev_number*10+last_digit;
        magic = magic / 10;

        last_digit = magic%10;
        rev_number = rev_number*10+last_digit;
        magic = magic/10;

        last_digit = magic%10;
        rev_number = rev_number*10+last_digit;
        magic = magic/10;

        if(rev_number == number)
        {
            printf("\nYour number %d is a MAGIC number\n", number);
        } else
        {
            printf("\nYour number %d is not a MAGIC number\n", number);
        }
    }
    else
    {
        printf("\nYou did not Enter a 3 digit number\n");
    }
}

Explanation:

The code extracts each digit of the number and reconstructs the reverse of the number. It then compares the original number with its reverse.

Sample Input/Output:

• Input: 121
• Output: Your number 121 is a MAGIC number.

Exercise 10 Output

Exercise 11: Check the Character Type

Question:

Any character is entered through the keyboard, write a program to determine whether the character entered is a capital letter, a small case letter, a digit or a special symbol.

Code:

#include <stdio.h>

int main()
{
    printf("\n----------------------------------------------------------");
    printf("\nThis program tells you the character type you've inputted");
    printf("\n----------------------------------------------------------");

    char ch;
    printf("\nEnter any character: ");
    scanf("%c", &ch);

    if(ch >= 'A' && ch <= 'Z')
    {
        printf("\nThe %c Character is a Capital Letter\n", ch);
    }
    else if(ch >= 'a' && ch <= 'z')
    {
        printf("\nThe %c Character is a Small letter\n", ch);
    }
    else if(ch >= '0' && ch <= '9')
    {
        printf("\nThe %c Character is a Digit\n", ch);
    }
    else
    {
        printf("\nThe %c Character is a Special Character\n", ch);
    }
}

Explanation:

The code uses if-ese statements and character comparisons to determine the character type:

• ch >= ‘A’ && ch <= ‘Z’ : Checks for uppercase letters.
• ch >= ‘a’ && ch <= ‘z’ : Checks for lowercase letters.
• ch >= ‘0’ && ch <= ‘9’ : Checks for digits.
• If none of the above conditions are met, the character is considered a special symbol.

Sample Input/Output:

Exercise 11 Output

• Input: A
• Output: The A Character is a Capital Letter.
• Input: *   (Try This)
• Output: The * Character is a Special Character.

Exercise 12: Leap Year (With Logical Operators)

Question:

Write a program using conditional operators to determine whether a year entered through the keyboard is a leap year or not.

Code:

#include <stdio.h>
int main()
{
    printf("\n-----------------------------------------------------------------");
    printf("\nThis program will check for Leap year using logical operator");
    printf("\n-----------------------------------------------------------------");

    int year;
    printf("\nEnter the year: ");
    scanf("%d", &year);

    ((year%4 == 0 && year%100 != 0) || (year%400 == 0))?
    printf("\nThe year %d is a leap year\n", year):printf("\nThe year %d is not a leap year\n", year);
}

Explanation:

The code uses the ternary operator (? :) and logical operators (&&, ||) to concisely check the leap year conditions:

• Year % 4 == 0 && year % 100 != 0 : The year is divisible by 4 and not divisible by 100
• Year % 400 == 0 : The year is divisible by 400.

Sample Input/Output:

Exercise 12 Output

• Input: 2024   (Try This)
• Output: The year 2024 is a leap year
  
• Input: 1900 
• Output: The year 1900 is not leap year.

I hope this post has been helpful! Feel free to experiment with these exercises and modify then to explore different approaches and enhance your understanding of C programming.

Don't forget to check our C programming page for more programming projects. 

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