Practical / Solution
if-else — Exercise 1
Problem
Write a C program to check whether a number is positive or negative.
Program
#include <stdio.h>
int main()
{
int num;
printf("Enter a number: ");
scanf("%d", &num);
// Check whether the number is positive
if (num >= 0)
printf("The number is positive.\n");
else
printf("The number is negative.\n");
return 0;
}
Explanation
The if block executes when the condition is true.
Otherwise, the else block executes.
Expected Output
Enter a number: -12
The number is negative.
if-else — Exercise 2
Problem
Write a C program to check whether a number is even or odd.
Program
#include <stdio.h>
int main()
{
int num;
printf("Enter a number: ");
scanf("%d", &num);
// Check divisibility by 2
if (num % 2 == 0)
printf("The number is even.\n");
else
printf("The number is odd.\n");
return 0;
}
Explanation
If the remainder after division by 2 is zero, the number is even;
otherwise, it is odd.
Expected Output
Enter a number: 17
The number is odd.
if-else — Exercise 3
Problem
Write a C program to check whether a student has passed or failed.
A student passes if marks are 50 or more.
Program
#include <stdio.h>
int main()
{
int marks;
printf("Enter marks: ");
scanf("%d", &marks);
// Check passing condition
if (marks >= 50)
printf("Pass.\n");
else
printf("Fail.\n");
return 0;
}
Explanation
The program compares the marks with 50. If the condition is true,
the student passes; otherwise, the student fails.
Expected Output
if-else — Exercise 4
Problem
Write a C program to find the greater of two numbers using if-else.
Program
#include <stdio.h>
int main()
{
int a, b;
printf("Enter two numbers: ");
scanf("%d %d", &a, &b);
// Compare the two numbers
if (a > b)
printf("%d is greater.\n", a);
else
printf("%d is greater or equal.\n", b);
return 0;
}
Explanation
The two numbers are compared. If a is greater than
b, a is displayed; otherwise, b
is displayed.
Expected Output
Enter two numbers: 25 40
40 is greater or equal.
if-else — Exercise 5
Problem
Write a C program to check whether a person is eligible to vote.
A person is eligible if the age is 18 or more.
Program
#include <stdio.h>
int main()
{
int age;
printf("Enter age: ");
scanf("%d", &age);
// Check voting eligibility
if (age >= 18)
printf("Eligible to vote.\n");
else
printf("Not eligible to vote.\n");
return 0;
}
Explanation
The condition checks whether the age is at least 18.
Both possible outcomes are handled by if-else.
Expected Output
Enter age: 16
Not eligible to vote.
if-else — Exercise 6
Problem
Write a C program to check whether a number is divisible by both 5 and 11.
Program
#include <stdio.h>
int main()
{
int num;
printf("Enter a number: ");
scanf("%d", &num);
// Check divisibility by both 5 and 11
if (num % 5 == 0 && num % 11 == 0)
printf("The number is divisible by both 5 and 11.\n");
else
printf("The number is not divisible by both 5 and 11.\n");
return 0;
}
Explanation
The logical AND operator && requires both
divisibility conditions to be true.
Expected Output
Enter a number: 55
The number is divisible by both 5 and 11.
if-else — Exercise 7
Problem
Write a C program to determine whether a character is a vowel or a consonant.
Program
#include <stdio.h>
int main()
{
char ch;
printf("Enter a character: ");
scanf(" %c", &ch);
// Check whether the character is a vowel
if (ch == 'a' || ch == 'e' || ch == 'i' ||
ch == 'o' || ch == 'u' ||
ch == 'A' || ch == 'E' || ch == 'I' ||
ch == 'O' || ch == 'U')
printf("The character is a vowel.\n");
else
printf("The character is a consonant.\n");
return 0;
}
Explanation
The character is compared with all five vowels in both lowercase
and uppercase forms.
Expected Output
Enter a character: E
The character is a vowel.
if-else — Exercise 8
Problem
Write a C program to check whether a year is a leap year.
Program
#include <stdio.h>
int main()
{
int year;
printf("Enter year: ");
scanf("%d", &year);
// Check leap year condition
if ((year % 400 == 0) ||
(year % 4 == 0 && year % 100 != 0))
printf("Leap year.\n");
else
printf("Not a leap year.\n");
return 0;
}
Explanation
A year is considered a leap year when it is divisible by 400,
or divisible by 4 but not by 100.
Expected Output
Enter year: 2024
Leap year.
if-else — Exercise 9
Problem
Write a C program to check whether a person receives a discount.
A discount is given when the purchase amount is 5000 or more.
Program
#include <stdio.h>
int main()
{
float amount;
printf("Enter purchase amount: ");
scanf("%f", &amount);
// Check discount eligibility
if (amount >= 5000)
printf("Discount is applicable.\n");
else
printf("Discount is not applicable.\n");
return 0;
}
Explanation
The purchase amount is compared with the minimum amount required
for the discount.
Expected Output
Enter purchase amount: 6500
Discount is applicable.
if-else — Exercise 10
Problem
Write a C program to check whether a number lies within the range
1 to 100.
Program
#include <stdio.h>
int main()
{
int num;
printf("Enter a number: ");
scanf("%d", &num);
// Check whether the number lies in the range
if (num >= 1 && num <= 100)
printf("The number is within the range.\n");
else
printf("The number is outside the range.\n");
return 0;
}
Explanation
The logical AND operator ensures that both conditions are true:
the number must be at least 1 and at most 100.
Expected Output
Enter a number: 75
The number is within the range.