Frequently Asked C Programming Questions in Interviews

1. Write a c program to check given number is perfect number or not.

2. Write a c program to check given number is Armstrong number or not.

3. Write a c program to check given number is prime number or not.

4. Write a c program to check given number is strong number or not.

5. C program to check a number is odd or even.

6. Write a c program to check given number is palindrome number or not.

8. Write a c program to check given string is palindrome number or not.
7. Write a c program to solve quadratic equation.
8.  Write a c program to print Fibonacci series of given range.
9. Write a c program to get factorial of given number.

10. Write a c program for Floyd’s triangle.

11. Write a c program to print Pascal triangle.

12. Write a c program to generate multiplication table.
13. Write a c program to print ASCII value of all characters.
14. C program to print hello world without using semicolon
15. Write a c program which produces its own source code as its output

C program with numbers


1. Write a c program to reverse any number.
2. Write a c program to find out sum of digit of given number.

3. Write a c program to find out power of number.          

4. Write a c program to add two numbers without using addition operator.

5. Write a c program to subtract two numbers without using subtraction operator.

6. Write a c program to find largest among three numbers using binary minus operator.

 7. Write a c program to find largest among three numbers using conditional operator

8. Write a c program to find out generic root of any number.

9. Write a c program to find out prime factor of given number.

10. Write a c program to find out NCR factor of given number.
11. How to convert string to int without using library functions in c
12. Program in c to print 1 to 100 without using loop
13. C program for swapping of two numbers
14. Program to find largest of n numbers in c
15. Split number into digits in c programming
16. C program to count number of digits in a number

Recursion
Example of recursion in c programming

L.C.M and H.C.F.

1.  Write a c program to find out L.C.M. of two numbers.

2. Write a c program to find out H.C.F. of two numbers.

3. Write a c program to find out G.C.D. of two numbers.

Swapping

1. Write a c program to swap two numbers.

2. Write a c program to swap two numbers without using third variable.

3. Write a c program for swapping of two arrays.

4. Write a c program for swapping of two string.

Conversion ( Number System )

1. Write a c program to convert decimal number to binary number.

2. Write a c program to convert decimal number to octal number.
3. Write a c program to convert decimal number to  hexadecimal number.
4. Write a c program to convert octal number to binary number.

5. Write a c program to convert octal number to decimal number.

6. Write a c program to convert octal number to hexadecimal number.

7. Write a c program to convert hexadecimal number to binary number.

8. Write a c program to convert hexadecimal number to octal number.
9. Write a c program to convert hexadecimal number to decimal number.
10. Write a c program to convert binary number to octal number.

11. Write a c program to convert binary number to decimal number.

12. Write a c program to convert binary number to hexadecimal number.
13. C program for addition of binary numbers . 
14. C program for multiplication of two binary numbers.
15. C program fractional binary conversion from decimal.
16. C program for fractional decimal to binary fraction conversion.
17. C program to convert decimal number to roman.
18. C program to convert roman number to decimal number.
19. C program to convert each digits of a number in words
20. C program to convert currency or number in word.

Conversion ( Unit )

1. C program for unit conversion.

String

1. Write a c program to convert the string from upper case to lower case.

2. Write a c program to convert the string from lower case to upper case.

3. Write a c program to delete the all consonants from given string.

4. Write a c program to count the different types of characters in given string.

5.  Write a c program to sort the characters of a string.

6. Write a c program for concatenation two strings without using string.h header file.

7. Write a c program to find the length of a string using pointer.  

8. Write a c program which prints initial of any name.

9. Write a c program to print the string from given character.
10. Write a c program to reverse a string
11. Reverse a string using recursion in c
12. String concatenation in c without using strcat
13. How to compare two strings in c without using strcmp
14. String copy without using strcpy in c
15. Convert a string to ASCII in c

Matrix

1. Write a c program for addition of two matrices.

2. Write a c program for subtraction of two matrices

3. Write a c program for multiplication of two matrices.

4. Write a c program to find out sum of diagonal element of a matrix.

5. Write a c program to find out transport of a matrix.
6. Write a c program for scalar multiplication of matrix.
7. C program to find inverse of a matrix
8. Lower triangular matrix in c
9. Upper triangular matrix in c
10. Strassen's matrix multiplication program in c
11. C program to find determinant of a matrix

File

1. Write a c program to open a file and write some text and close its.

2.  Write a c program to delete a file.

3. Write a c program to copy a file from one location to other location.

4. Write a c program to copy a data of file to other file.

5. Write a c program which display source code as a output.

6. Write a c program which writes string in the file.

7. Write a c program which reads string from file.

8. Write a c program which writes array in the file.

9. Write a c program which concatenate two file and write it third file.
10. Write a c program to find out size of any file.
11. Write a c program to know type of file.
12. Write a c program to know permission of any file.
13. Write a c program to know last date of modification of any file.
14. Write a c program to find size and drive of any file.

Complex number

1. Complex numbers program in c

2. Write a c program for addition and subtraction of two complex numbers.

3. Write a c program for multiplication of two complex numbers.

4. Write a c program for division two complex numbers.

Series

1. Write a c program to find out the sum of series 1 + 2 + ….  + n.

2. Write a c program to find out the sum of series 1^2 + 2^2 + …. + n^2.

3. Write a c program to find out the sum of series 1^3 + 2^3 + …. + n^3.

4. Write a c program to find out the sum of given A.P.

5. Write a c program to find out the sum of given G.P.

6. Write a c program to find out the sum of given H.P.

7. Write a c program to find out the sum of series 1 + 2 + 4 + 8 … to infinity.

Array

1. Write a c program to find out largest element of an array.

2. Write a c program to find out second largest element of an unsorted array.

3. Write a c program to find out second smallest element of an unsorted array.

4. Write a c program which deletes the duplicate element of an array.

5. Write a c program for delete an element at desired position in an array.

6. Write a c program for insert an element at desired position in an array.
7. C program to find largest and smallest number in an array

Sorting

1. Write a c program for bubble sort.

2. Write a c program for insertion sort.

3. Write a c program for selection sort.

4. Write a c program for quick sort.

5. Write a c program for heap sort.

6. Write a c program for merge sort.

7. Write a c program for shell sort.

Recursion

1. Write a c program to find factorial of a number using recursion.

2. Write a c program to find GCD of a two numbers using recursion.

3. Write a c program to find out sum digits of a number using recursion.

4. Write a c program to find power of a number using function recursion.

5. Write a c program to reverse any number using recursion.

Size of data type

1. Write a c program to find the size of int without using sizeof operator.

2. Write a c program to find the size of double without using sizeof operator.     

3. Write a c program to find the size of structure without using sizeof operator.

4. Write a c program to find the size of union without using sizeof operator.

Using pointer

1. Write a c program for concatenation two string using pointer.

Searching

1. Write a c program for linear search.

2. Write a c program for binary search.

3. Write a c program for binary search using recursion.

Area and volume

1. Write a c program to find the area of circle.

2. Write a c program to find the area of any triangle.
3. Write a c program to find the area of equilateral triangle.
4. Write a c program to find the area of right angled triangle.

5. Write a c program to find the area of rectangle.

6. Write a c program to find the area of trapezium.     
7. Write a c program to find the area of rhombus.   
8. Write a c program to find the area of parallelogram.           

9. Write a c program to find the volume and surface area of cube.
10. Write a c program to find the volume and surface area of cuboids.
11. Write a c program to find the volume and surface area of cylinder.

12. Write a c program to find the surface area and volume of a cone.
13. Write a c program to find the volume and surface area of sphere.

14. Write a c program to find the perimeter of a circle, rectangle and triangle.


C program with very large numbers


1. Write a c program to find factorial of 100 or very large numbers
2. Write a c program to multiply the two very large number (larger the long int)
3. Write a c program for division of large number (larger than long int)
4. C code for modular division of large number.
5. C code for division of large number.
6. C code for power of large numbers.


Other


1. C program for ATM transaction.

2. Write a c program which passes one dimension array to function.

3. Write a c program which passes two dimension array to function.

4. Write a c program which takes password from user.

5. Write a scanf function in c which accept sentence from user.

6. Write a scanf function in c which accept paragraph from user.

7. Write a c program to print the all prime numbers between 1 to 300.
8. Write a c program which passes structure to function.
9. Palindrome in c without using string function
10. How to get the ASCII value of a character in c
11. C program to get last two digits of year
12. C program without main function