1.

Variables and Datatypes

Q1. Write a C program to declare two integer variables and display their sum.
#include <stdio.h>
int main() {
int a, b;
printf("Enter two integers: ");
scanf("%d %d", &a, &b);
printf("Sum = %d\n", a + b);
return 0;
}
Test cases:
- Input: 10, 20 → Output: 30
- Input: -5, 15 → Output: 10
- Input: 0, 0 → Output: 0

Q2. Write a program to declare a float variable, input its value, and display it with 2 decimal
places.
```c
#include <stdio.h>
int main() {
float num;
printf("Enter a float number: ");
scanf("%f", &num);
printf("You entered: %.2f\n", num);
return 0;
}
```
Test cases:
- Input: 12.345 → Output: 12.35
- Input: 0 → Output: 0.00
- Input: -56.789 → Output: -56.79

---

Q3. Write a C program to calculate the area of a rectangle using integer inputs for length
and width.
```c
#include <stdio.h>
int main() {
int length, width;
printf("Enter length and width: ");
scanf("%d %d", &length, &width);
printf("Area = %d\n", length width);
return 0;
}
```
Test cases:
- Input: 5, 10 → Output: 50
- Input: 3, 4 → Output: 12
- Input: 7, 0 → Output: 0

---

2. Input and Output Statements

Q4. Write a program to input a character and print its ASCII value.
```c
#include <stdio.h>
int main() {
char c;
printf("Enter a character: ");
scanf("%c", &c);
printf("ASCII value of %c = %d\n", c, c);
return 0;
}
```
Test cases:
- Input: A → Output: ASCII value of A = 65
- Input: z → Output: ASCII value of z = 122
- Input: 3 → Output: ASCII value of 3 = 51

---

Q5. Write a program to read three integers and print their average.
```c
#include <stdio.h>
int main() {
int a, b, c;
printf("Enter three integers: ");
scanf("%d %d %d", &a, &b, &c);
printf("Average = %.2f\n", (a + b + c) / 3.0);
return 0;
}
```
Test cases:
- Input: 5, 10, 15 → Output: Average = 10.00
- Input: -2, 0, 2 → Output: Average = 0.00
- Input: 1, 1, 1 → Output: Average = 1.00

---

Q6. Write a program to input a string and print it.

```c
#include <stdio.h>
int main() {
char str[100];
printf("Enter a string: ");
scanf("%s", str);
printf("You entered: %s\n", str);
return 0;
}
```
Test cases:
- Input: Hello → Output: You entered: Hello
- Input: CProgramming → Output: You entered: CProgramming
- Input: Code123 → Output: You entered: Code123

---

3. Control Flow - If-Else Statements

Q7. Write a program to check if a number is positive, negative, or zero.
```c
#include <stdio.h>
int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);
if (num > 0)
printf("Positive\n");
else if (num < 0)
printf("Negative\n");
else
printf("Zero\n");
return 0;
}
```
Test cases:
- Input: 5 → Output: Positive
- Input: -7 → Output: Negative
- Input: 0 → Output: Zero

---

Q8. Write a program to check if a number is even or odd.

```c
#include <stdio.h>
int main() {
int num;
 printf("Enter a number: ");
scanf("%d", &num);
if (num % 2 == 0)
printf("Even\n");
else
printf("Odd\n");
return 0;
}
```
Test cases:
- Input: 4 → Output: Even
- Input: 7 → Output: Odd
- Input: 0 → Output: Even

---

Q9. Write a program to check if a person is eligible to vote (age >= 18).
```c
#include <stdio.h>
int main() {
int age;
printf("Enter your age: ");
scanf("%d", &age);
if (age >= 18)
printf("Eligible to vote\n");
else
printf("Not eligible to vote\n");
return 0;
}
```
Test cases:
- Input: 20 → Output: Eligible to vote
- Input: 16 → Output: Not eligible to vote
- Input: 18 → Output: Eligible to vote

---

4. Control Flow - Switch Statement

Q10. Write a program to input a day number (1-7) and print the corresponding day of the
week.
```c
#include <stdio.h>
int main() {
int day;
printf("Enter day number (1-7): ");
scanf("%d", &day);
switch (day) {
case 1: printf("Sunday\n"); break;
case 2: printf("Monday\n"); break;
case 3: printf("Tuesday\n"); break;
case 4: printf("Wednesday\n"); break;
case 5: printf("Thursday\n"); break;
case 6: printf("Friday\n"); break;
case 7: printf("Saturday\n"); break;
default: printf("Invalid day\n");
 }
return 0;
}
```
Test cases:
- Input: 1 → Output: Sunday
- Input: 4 → Output: Wednesday
- Input: 8 → Output: Invalid day

---

Q11. Write a program to input a character and print whether it is a vowel or consonant
using a switch statement.
```c
#include <stdio.h>
int main() {
char c;
printf("Enter a character: ");
scanf(" %c", &c);
switch (c) {
case 'a': case 'e': case 'i': case 'o': case 'u':
case 'A': case 'E': case 'I': case 'O': case 'U':
printf("Vowel\n");
break;
default:
printf("Consonant\n");
}
return 0;
}
```
Test cases:
- Input: a → Output: Vowel
- Input: B → Output: Consonant
- Input: e → Output: Vowel

---

5. Nested Conditional Statements

Q12. Write a program to find the largest of three numbers using nested if-else statements.
```c
#include <stdio.h>
int main() {
int a, b, c;
printf("Enter three numbers: ");
scanf("%d %d %d", &a, &b, &c);
if (a >= b) {
if (a >= c)
printf("%d is the largest\n", a);
else
printf("%d is the largest\n", c);
} else {
if (b >= c)
printf("%d is the largest\n", b);
else
printf("%d is the largest\n", c);
 }
return 0;
}
```
Test cases:
- Input: 10, 20, 30 → Output: 30 is the largest
- Input: 50, 25, 10 → Output: 50 is the largest
- Input: 15, 15, 15 → Output: 15 is the largest

---

Q13. Write a program to check if a year is a leap year using nested if-else statements.
```c
#include <stdio.h>
int main() {
int year;
printf("Enter a year: ");
scanf("%d", &year);
if (year % 4 == 0) {
if (year % 100 == 0) {
if (year % 400 == 0)
printf("%d is a leap year\n", year);
else
printf("%d is not a leap year\n", year);
} else
printf("%d is a leap year\n", year);
} else
printf("%d is not a leap year\n", year);
 return 0;
}
```
Test cases:
- Input: 2024 → Output: 2024 is a leap year
Here are 20 more test case-based C programming questions, continuing from the previous
topics of variables and datatypes, input/output statements, control flow (if-else, switch),
and nested conditional statements:

6. Control Flow - Nested Conditional Statements (Continued)

Q14. Write a program to categorize a person's age into a life stage (Child, Teenager, Adult,
Senior) using nested if-else.
```c
#include <stdio.h>
int main() {
int age;
printf("Enter your age: ");
scanf("%d", &age);
if (age < 13)
printf("Child\n");
else if (age < 20)
printf("Teenager\n");
else if (age < 60)
printf("Adult\n");
else
printf("Senior\n");
return 0;
}
```
Test cases:
- Input: 10 → Output: Child
- Input: 16 → Output: Teenager
- Input: 45 → Output: Adult
- Input: 75 → Output: Senior

---

Q15. Write a program to check if a number is divisible by both 3 and 5 using nested if-else.
```c
#include <stdio.h>
int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);
if (num % 3 == 0) {
if (num % 5 == 0)
printf("Divisible by both 3 and 5\n");
else
printf("Divisible by 3 but not by 5\n");
} else
printf("Not divisible by 3\n");
return 0;
}
```
Test cases:
- Input: 15 → Output: Divisible by both 3 and 5
- Input: 9 → Output: Divisible by 3 but not by 5
- Input: 7 → Output: Not divisible by 3

---

Q16. Write a program to find the smallest of three numbers using nested if-else statements.
```c
#include <stdio.h>
int main() {
int a, b, c;
printf("Enter three numbers: ");
scanf("%d %d %d", &a, &b, &c);
if (a <= b) {
if (a <= c)
printf("%d is the smallest\n", a);
else
printf("%d is the smallest\n", c);
} else {
if (b <= c)
printf("%d is the smallest\n", b);
else
printf("%d is the smallest\n", c);
}
return 0;
}
```
Test cases:
- Input: 10, 20, 5 → Output: 5 is the smallest
- Input: 15, 5, 30 → Output: 5 is the smallest
- Input: 25, 25, 25 → Output: 25 is the smallest

---

Q17. Write a program to categorize a number as positive, negative, or zero using nested if-
else.
```c
#include <stdio.h>
int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);
if (num > 0)
printf("Positive\n");
else if (num < 0)
printf("Negative\n");
else
printf("Zero\n");
return 0;
}
```
Test cases:
- Input: 10 → Output: Positive
- Input: -8 → Output: Negative
- Input: 0 → Output: Zero

---
7. Control Flow - Switch Statements (Continued)

Q18. Write a program to input a grade character (A, B, C, D, F) and print the corresponding
performance using a switch statement.
```c
#include <stdio.h>
int main() {
char grade;
printf("Enter a grade (A, B, C, D, F): ");
scanf(" %c", &grade);
switch (grade) {
case 'A': printf("Excellent\n"); break;
case 'B': printf("Good\n"); break;
case 'C': printf("Average\n"); break;
case 'D': printf("Below Average\n"); break;
case 'F': printf("Fail\n"); break;
default: printf("Invalid grade\n");
}
return 0;
}
```
Test cases:
- Input: A → Output: Excellent
- Input: C → Output: Average
- Input: F → Output: Fail
- Input: G → Output: Invalid grade
---

Q19. Write a program to input a number (1-12) and print the corresponding month name
using a switch statement.
```c
#include <stdio.h>
int main() {
int month;
printf("Enter month number (1-12): ");
scanf("%d", &month);
switch (month) {
case 1: printf("January\n"); break;
case 2: printf("February\n"); break;
case 3: printf("March\n"); break;
case 4: printf("April\n"); break;
case 5: printf("May\n"); break;
case 6: printf("June\n"); break;
case 7: printf("July\n"); break;
case 8: printf("August\n"); break;
case 9: printf("September\n"); break;
case 10: printf("October\n"); break;
case 11: printf("November\n"); break;
case 12: printf("December\n"); break;
default: printf("Invalid month\n");
}
return 0;
}
```
Test cases:
- Input: 5 → Output: May
- Input: 11 → Output: November
- Input: 13 → Output: Invalid month

---

8. Input/Output Statements (Continued)

Q20. Write a program to input a number and print its square and cube.
```c
#include <stdio.h>
int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);
printf("Square = %d\n", num num);
printf("Cube = %d\n", num num num);
return 0;
}
```
Test cases:
- Input: 3 → Output: Square = 9, Cube = 27
- Input: 5 → Output: Square = 25, Cube = 125
- Input: -2 → Output: Square = 4, Cube = -8

---
Q21. Write a program to input two floating-point numbers and display their product.
```c
#include <stdio.h>
int main() {
float a, b;
printf("Enter two numbers: ");
scanf("%f %f", &a, &b);
printf("Product = %.2f\n", a b);
return 0;
}
```
Test cases:
- Input: 2.5, 3.6 → Output: Product = 9.00
- Input: -4.1, 5.2 → Output: Product = -21.32
- Input: 0, 3.3 → Output: Product = 0.00

---

Q22. Write a program to input an integer and print its binary representation.
```c
#include <stdio.h>
int main() {
int num;
printf("Enter an integer: ");
scanf("%d", &num);
printf("Binary: ");
for (int i = 31; i >= 0; i--)
printf("%d", (num >> i) & 1);
 printf("\n");
return 0;
}
```
Test cases:
- Input: 5 → Output: Binary: 00000000000000000000000000000101
- Input: 10 → Output: Binary: 00000000000000000000000000001010
- Input: 255 → Output: Binary: 00000000000000000000000011111111

---

9. Control Flow - If-Else (Continued)

Q23. Write a program to check whether a number is prime using if-else.

```c
#include <stdio.h>
int main() {
int num, flag = 0;
printf("Enter a number: ");
scanf("%d", &num);
if (num <= 1)
printf("Not Prime\n");
else {
for (int i = 2; i <= num / 2; i++) {
if (num % i == 0) {
flag = 1;
break;
}
 }
if (flag == 0)
printf("Prime\n");
else
printf("Not Prime\n");
}
return 0;
}
```
Test cases:
- Input: 7 → Output: Prime
- Input: 9 → Output: Not Prime
- Input: 1 → Output: Not Prime

---

Q24. Write a program to check if a number is a palindrome using if-else.

```c
#include <stdio.h>
int main() {
int num, reversed = 0, original, remainder;
printf("Enter an integer: ");
scanf("%d", &num);
original = num;
while (num != 0) {
remainder

Here are 10 more test case-based C programming questions:

### 10. Control Flow - If-Else Statements (Continued)

**Q25.** Write a program to find if a number is positive, negative, or zero using a nested if-
else statement.
```c
#include <stdio.h>
int main() {
int num;
printf("Enter a number: ");
scanf("%d", &num);
if (num > 0)
printf("Positive\n");
else if (num < 0)
printf("Negative\n");
else
printf("Zero\n");
return 0;
}
```
*Test cases:*
- Input: 25 → Output: Positive
- Input: -13 → Output: Negative
- Input: 0 → Output: Zero

---

**Q26.** Write a program to input the length and width of a rectangle, and determine if it is
a square.
```c
#include <stdio.h>
int main() {
int length, width;
printf("Enter length and width: ");
scanf("%d %d", &length, &width);
if (length == width)
printf("It is a square\n");
else
printf("It is not a square\n");
return 0;
}
```
*Test cases:*
- Input: 5, 5 → Output: It is a square
- Input: 7, 10 → Output: It is not a square
- Input: 4, 4 → Output: It is a square

---

**Q27.** Write a program to check if a character is an uppercase or lowercase letter using

if-else.
```c
#include <stdio.h>
int main() {
char ch;
printf("Enter a character: ");
scanf(" %c", &ch);
 if (ch >= 'A' && ch <= 'Z')
printf("Uppercase\n");
else if (ch >= 'a' && ch <= 'z')
printf("Lowercase\n");
else
printf("Not a letter\n");
return 0;
}
```
*Test cases:*
- Input: A → Output: Uppercase
- Input: g → Output: Lowercase
- Input: 5 → Output: Not a letter

---

**Q28.** Write a program to find whether a given year is a leap year or not using if-else.
```c
#include <stdio.h>
int main() {
int year;
printf("Enter a year: ");
scanf("%d", &year);
if (year % 400 == 0 || (year % 100 != 0 && year % 4 == 0))
printf("%d is a leap year\n", year);
else
printf("%d is not a leap year\n", year);
return 0;
}
```
*Test cases:*
- Input: 2020 → Output: 2020 is a leap year
- Input: 1900 → Output: 1900 is not a leap year
- Input: 2000 → Output: 2000 is a leap year

---

**Q29.** Write a program to input two numbers and check whether they are divisible by
each other using if-else.
```c
#include <stdio.h>
int main() {
int a, b;
printf("Enter two numbers: ");
scanf("%d %d", &a, &b);
if (a % b == 0)
printf("%d is divisible by %d\n", a, b);
else if (b % a == 0)
printf("%d is divisible by %d\n", b, a);
else
printf("Neither number is divisible by the other\n");
return 0;
}
```
*Test cases:*
- Input: 10, 5 → Output: 10 is divisible by 5
- Input: 4, 16 → Output: 16 is divisible by 4
- Input: 7, 3 → Output: Neither number is divisible by the other

---

### 11. Switch Statements (Continued)

**Q30.** Write a program to input a number from 1 to 4 and print the corresponding
season (1: Winter, 2: Spring, 3: Summer, 4: Autumn) using a switch statement.
```c
#include <stdio.h>
int main() {
int season;
printf("Enter a number (1-4): ");
scanf("%d", &season);
switch (season) {
case 1: printf("Winter\n"); break;
case 2: printf("Spring\n"); break;
case 3: printf("Summer\n"); break;
case 4: printf("Autumn\n"); break;
default: printf("Invalid input\n");
}
return 0;
}
```
*Test cases:*
- Input: 1 → Output: Winter
- Input: 3 → Output: Summer
- Input: 5 → Output: Invalid input

---

**Q31.** Write a program to input a number from 1 to 3 and print the corresponding traffic
light (1: Red, 2: Yellow, 3: Green) using a switch statement.
```c
#include <stdio.h>
int main() {
int light;
printf("Enter a number (1-3): ");
scanf("%d", &light);
switch (light) {
case 1: printf("Red\n"); break;
case 2: printf("Yellow\n"); break;
case 3: printf("Green\n"); break;
default: printf("Invalid input\n");
}
return 0;
}
```
*Test cases:*
- Input: 1 → Output: Red
- Input: 3 → Output: Green
- Input: 4 → Output: Invalid input

---
**Q32.** Write a program to input a number from 1 to 5 and print the corresponding grade
description (1: Excellent, 2: Good, 3: Average, 4: Poor, 5: Fail) using a switch statement.
```c
#include <stdio.h>
int main() {
int grade;
printf("Enter a number (1-5): ");
scanf("%d", &grade);
switch (grade) {
case 1: printf("Excellent\n"); break;
case 2: printf("Good\n"); break;
case 3: printf("Average\n"); break;
case 4: printf("Poor\n"); break;
case 5: printf("Fail\n"); break;
default: printf("Invalid input\n");
}
return 0;
}
```
*Test cases:*
- Input: 2 → Output: Good
- Input: 5 → Output: Fail
- Input: 6 → Output: Invalid input

---

### 12. Input/Output Statements (Continued)

**Q33.** Write a program to input a character and check if it is a digit, a letter, or a special
character.
```c
#include <stdio.h>
int main() {
char ch;
printf("Enter a character: ");
scanf(" %c", &ch);
if (ch >= '0' && ch <= '9')
printf("Digit\n");
else if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z'))
printf("Letter\n");
else
printf("Special character\n");
return 0;
}
```
*Test cases:*
- Input: 5 → Output: Digit
- Input: A → Output: Letter
- Input: $ → Output: Special character

---

**Q34.** Write a program to input the radius of a circle and print its circumference and
area.
```c
#include <stdio.h>
#define PI 3.14159
int main() {
float radius;
printf("Enter radius: ");
scanf("%f", &radius);
printf("Circumference = %.2f\n", 2 * PI * radius);
printf("Area = %.2f\n", PI * radius * radius);
return 0;
}
```
*Test cases:*
- Input: 3 → Output: Circumference = 18.85, Area = 28.27
- Input: 5 → Output: Circumference = 31.42, Area = 78.54
- Input: 0 → Output: Circumference = 0.00, Area = 0.00

---

**Q35.** Write a program to input a number and find the sum of its digits.
```c
#include <stdio.h>
int main() {
int num, sum = 0;
printf("Enter a number: ");
scanf("%d", &num);
while (num != 0) {
sum += num % 10;
num /= 10;
}
printf("Sum of digits = %d\n", sum);
 return 0;
}
```
*Test cases:*
- Input: 123 → Output: Sum of digits = 6
- Input: 456 → Output: Sum of digits = 15
- Input: 9 → Output: Sum of digits = 9