1. Given a Binary Search Tree, write a program to print the kth smallest element without using any static/global variable. You can’t pass the value k to any function also.
2. What are the 4 basics of OOP?
3. Define Data Abstraction. What is its importance?
4. Given an array of size n. It contains numbers in the range 1 to n. Each number is present at least once except for 2 numbers. Find the missing numbers.
5. Given an array of size n. It contains numbers in the range 1 to n. Find the numbers which aren’t present.
6. Given a string,find the first un-repeated character in it? Give some test cases
7. You are given a dictionary of all valid words. You have the following 3 operations permitted on a word: delete a character, insert a character, replace a character. Now given two words - word1 and word2 - find the minimum number of steps required to convert word1 to word2. (one operation counts as 1 step.)
8. Given a cube of size n*n*n (i.e made up of n^3 smaller cubes), find the number of smaller cubes on the surface. Extend this to k-dimension.
9. What is a C array and illustrate the how is it different from a list.
10. What is the time and space complexities of merge sort and when is it preferred over quick sort?
11. Write a function which takes as parameters one regular expression(only ? and * are the special characters) and a string and returns whether the string matched the regular expression.
12. Given n red balls and m blue balls and some containers, how would you distribute those balls among the containers such that the probability of picking a red ball is maximized, assuming that the user randomly chooses a container and then randomly picks a ball from that.
13. Find the second largest element in an array with minimum no of comparisons and give the minimum no of comparisons needed on an array of size N to do the same.
14. Given an array of size n, containing every element from 1 to n+1, except one. Find the missing element.
15. How do you convert a decimal number to its hexa-decimal equivalent.Give a C code to do the same
16. Explain polymorphism. Provide an example.
17. Given an array all of whose elements are positive numbers, find the maximum sum of a subsequence with the constraint that no 2 numbers in the sequence should be adjacent in the array. So 3 2 7 10 should return 13 (sum of 3 and 10) or 3 2 5 10 7 should return 15 (sum of 3, 5 and 7)
18. You are given some denominations of coins in an array (int denom[])and infinite supply of all of them. Given an amount (int amount), find the minimum number of coins required to get the exact amount. What is the method called?
19. Given an array of size n. It contains numbers in the range 1 to n. Each number is present at least once except for 1 number. Find the missing number.

1. What is the most efficient way to reverse a linklist?
2. How to sort & search a single linklist?
3. Which is more convenient - single or double-linked linklist? Discuss the trade-offs? What about XOR-linked linklist?
4. How does indexing work?
5. char s[10];
s=”Hello”;
printf(s);
   What will be the output? Is there any error with this code?
6. What is the difference between
   char s[]=”Hello”;
char *s=”Hello”;
   Please give a clear idea on this?
7. Why do we pass a reference for copy constructors? If it does shallow copy for pass by value (user defined object), how will it do the deep copy?
8. What is the difference between shallow copy & deep copy?
9. What is the difference between strcpy and memcpy? What rule should we follow when choosing between these two?
10. If we declare two variable and two applications are using the same variable, then what will its value be, will it be the same?

1. What is a void return type?
2. How is it possible for two String objects with identical values not to be equal under the == operator?
3. What is the difference between a while statement and a do statement?
4. Can a for statement loop indefinitely?
5. How do you link a C++ program to C functions?
6. How can you tell what shell you are running on UNIX system?

Implementing itoa function is a popular interview question. Here’s one implementation from SAP.

char *itoa(int value)
{
int count, /* number of characters in string */
i, /* loop control variable */
sign; /* determine if the value is negative */
char *ptr, /* temporary pointer, index into string */
*string, /* return value */
*temp; /* temporary string array */

return(string);
}


1. Are you familiar with the term MESI?
2. Are you familiar with the term snooping?
3. Describe a finite state machine that will detect three consecutive coin tosses (of one coin) that results in heads.
4. In what cases do you need to double clock a signal before presenting it to a synchronous state machine?
5. You have a driver that drives a long signal & connects to an input device. At the input device there is either overshoot, undershoot or signal threshold violations, what can be done to correct this problem?
6. For a single computer processor computer system, what is the purpose of a processor cache and describe its operation?
7. Explain the operation considering a two processor computer system with a cache for each processor.
8. What are the main issues associated with multiprocessor caches and how might you solve it?
9. Explain the difference between write through and write back cache.
10. What are the total number of lines written in C/C++? What is the most complicated/valuable program written in C/C++?
11. What compiler was used?
12. Have you studied busses? What types?
13. Have you studied pipelining? List the 5 stages of a 5 stage pipeline. Assuming 1 clock per stage, what is the latency of an instruction in a 5 stage machine? What is the throughput of this machine ?
14. How many bit combinations are there in a byte?
15. What is the difference between = and == in C?
16. Are you familiar with VHDL and/or Verilog?

1. How do you write a program which produces its own source code as its output?
2. How can I find the day of the week given the date?
3. Why doesn’t C have nested functions?
4. What is the most efficient way to count the number of bits which are set in a value?
5. How can I convert integers to binary or hexadecimal?
6. How can I call a function, given its name as a string?
7. How do I access command-line arguments?
8. How can I return multiple values from a function?
9. How can I invoke another program from within a C program?
10. How can I access memory located at a certain address?
11. How can I allocate arrays or structures bigger than 64K?
12. How can I find out how much memory is available?
13. How can I read a directory in a C program?
14. How can I increase the allowable number of simultaneously open files?
15. What’s wrong with the call fopen(”c:\newdir\file.dat”, “r”)?

1. Will the following program execute?void main()
{
void *vptr = (void *) malloc(sizeof(void));
vptr++;
}
2. How about this one?
   void main()
{
char *cptr = 0?2000;
long *lptr = 0?2000;
cptr++;
lptr++;
printf(” %x %x”, cptr, lptr);
}Will it execute or not?
3. When the processor wakes up after power on, it goes to a particular memory location. What is that memory location called?
4. What is the difference between Mutex and Binary semaphore?
5. Write a program to set 2nd bit in a 32 bit register with memory location 0×2000?

1. What are the total number of lines written in C/C++? What is the most complicated/valuable program written in C/C++?
2. What compiler was used?
3. Have you studied buses? What types?
4. Have you studied pipelining? List the 5 stages of a 5 stage pipeline. Assuming 1 clock per stage, what is the latency of an instruction in a 5 stage machine? What is the throughput of this machine ?
5. How many bit combinations are there in a byte?
6. What is the difference between = and == in C?
7. Are you familiar with VHDL and/or Verilog?

This set of C++ interview questions was sent to TechInterviews from Australia:

1. What is the difference between an ARRAY and a LIST?
2. What is faster : access the element in an ARRAY or in a LIST?
3. Define a constructor - what it is and how it might be called (2 methods).
4. Describe PRIVATE, PROTECTED and PUBLIC – the differences and give examples.
5. What is a COPY CONSTRUCTOR and when is it called (this is a frequent question !)?
6. Explain term POLIMORPHISM and give an example using eg. SHAPE object: If I have a base class SHAPE, how would I define DRAW methods for two objects CIRCLE and SQUARE.
7. What is the word you will use when defining a function in base class to allow this function to be a polimorphic function?
8. What are 2 ways of exporting a function from a DLL?
9. You have two pairs: new() and delete() and another pair : alloc() and free(). Explain differences between eg. new() and malloc()
10. What is a callback function. Explain in C and C++ and WIN API environment.
11. (From WINDOWS API area): what is LPARAM and WPARAM?

This is not really a set of interview questions, a reader sent TechInterviews.com what looks like a copy of his notes from C++ class that describes various tricks and code for C++.

1. What is the output of printf(“%d”)?
   1. %d helps to read integer data type of a given variable
   2. when we write (“%d”, X) compiler will print the value of x assumed in the main
   3. but nothing after (“%d”) so the output will be garbage
   4. printf is an overload function doesnt check consistency of the arg list – segmentation fault
2. What will happen if I say delete this? - destructor executed, but memory will not be freed (other than work done by destructor). If we have class Test and method Destroy { delete this } the destructor for Test will execute, if we have Test *var = new Test()
   1. pointer var will still be valid
   2. object created by new exists until explicitly destroyed by delete
   3. space it occupied can be reused by new
   4. delete may only be applied to a pointer by new or zero, applying delete to zero = no FX
   5. delete = delete objects
   6. delete[] – delete array
   7. delete operator destroys the object created with new by deallocating the memory assoc. with the object
   8. if a destructor has been defined fir a class delete invokes that desructor

1. How did you first get interested in Computer Science?
2. What do you like to do best related to computers now (programming, administration, testing, manage projects, etc)? What is it about that area that you specifically enjoy?
3. What is your strongest programming language (Java, ASP, C, C++, VB, HTML,C#, etc.)?
4. When is the last time you coded in C/C++? What is the most lines of original C/C++ code you have personally written in one project? How confident are you in your ability to write C or C++ without a reference?

• Write function in C that gets array of chars, and search for the longest sequence of repeatedly 1 bits. It returns the the first bit place in the sequence and the number of 1 bits in the sequence. - (a) loop of 2^0, 2^1, … , 2^7 is done with 1<<j when 0<=j<=7. (b) Take care of remembering the first place of the bit sequence you are counting.
• You have 16bit register that increment itself and loops about every second. When the register reach 0xffff it will issue an interupt and will run the function update_time(). There is a function unsigned long get_time() that returns the time. You need to implement the two functions. - (a) You need to count every interrupt in order to save the number of seconds. (b) The counter will be the 16bit MSB, and the actual register will be 16bit LSB. (c) If the register will be at ~0xfff0, you will return MSB that is not correct, because you will read the counter, then interrupt will accure and increment by one. Now you have counter that is not correct. (d) You need to check for the (c) problem, and if you catch the problem, you need to read once again the register and the counter before you return them. You depend on the fact the you have about another second until the register will loop.