C and Data Structures Interview Questions Collections

General C Questions

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How C program compiles and linking ?

GCC and it's options, what is make file ?

What is volatile ? Why we go for vollt ? What is optimization ?

Example program of volatile ? Applications using volatile variable ? Where it will store in RAM ? Can a variable be both const and volatile?

What is Static ? applications of static keyword ? if i extern a static variable, which stage that error will be identified ? Scope ?

Different type of datatypes ? int,uint,char.. long ?

What if do multiply unit,int ? that cast conversion is needed ?

What is the application of const qualifier ?

What is reg data type ? where you use it ? Scope ?

All mem related functions like memcpy, memmove,

memchr, memset, bzero ? Esxpecially How do you find overlap in memmove and how do you copy data from src to dest ?

Swap two variables without using temp, ExoR, single line, using +,-

How does free() knows allocated memory ?

How do you define a variable argument function ? Use va_arg, va_start,va_end macros.

How do you find the size of a variable without using sizeof opr?

What is recursion and applications of recursive ?

Get the inputs like 10,20,30,40,50 and print it in reverse order, Dont use array. Dont expect Stack-LinkedList implementation. Use recursive method.

Four parts of RAM and what are the variables stored in all fours parts? BSS ? How BSS value gets intialized ?

How do you print value stores in 0x00123 address ? Can we assign the address to a pointer ? Might be in DOS, far pointer concepts.

How do you avoid twice inclusion of same header file ? using #if define

Write a program to find the square root of the number without using the any mathematical function ?

Is size of int depends on machine or compiler ? size of pointer ?

ARRAY:

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In an array, linear search, binary search,

How do you find duplicate in an array and remove it ?

Addition/Deletion of an element in an array at n th position ?

Reverse of an array[string,int]

sorting an array[bubble,select,...look DS Questions]

Memory allocation for single dimension array, two dimentsional array, three dimension array using malloc. Differnt ways of allocation memory for 2 dimen array.

How do you pass all the arrays to a func ?

How do you intialize all the dimensional arrays ? What is the value of other location if the array is partially initialized ?

static array means ? application ?

Array of pointers, pointer to an array ? array of funtion pointers ?

How do you intialize above pointers ?

Matrix addition, multiplications.

STRING:

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Defintions for all string handling functions like 

strlen,strcpy,strncpy,strcat,strncat,strstr,strrev

strrev - using recursive, without any buffer

strstr - own defintions

strcmp - ow defn

Reverse the words from a statement ? I am a boy==> boy a am I

insert word in between given string

Where string constant will store ? scope of that const ?

Find out the no of words,lines,chars in a given file ?

find the length of given string buffer, without using loop and str func. Use printf

FUNCTION:

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function pointer ? different set of fptr declarations ?

know the spiral rule ? declare a fptr returns fptr itself ?

call by value/call by reference

Stack is related to a func or a process[Moto] ?

How does the stack grows when a f1 calls f2 ? Draw and explain how local var, return add is being stored ? SP,PC reg ?

argc,argv means ? usage of that variables ?

What is function prototype ?

What is inline func and why do we need ?

what is reentrant function ? where it stores ?

Write a function to add two 16-bit numbers it will return

      TRUE  -  in case of overflow in the result

      FLASE - if there is no overflow

How do you manage 2 stacks using single array of buffer ?

BITWISE OPERATIONS:

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How do you set/reset a bit in an integar ?

Count of no of bits set in an int ?

Reverse the bits in an int ?

Find out the given no id odd/even and power of two ?

What is little/big endian, find out machine endian ?

Convert big to little endian and viceversa ? ntoh ? hton ?

Multiply the given two nos withoug using * ?

Swap two bits in an integar ?

Convert int<->binary int to hex, int to hex, Get to know the common function definition.

Sum of digits of given no ? Palindrome ?

STRUCTURE AND UNION:

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Difference btw struct and union ?

Struct padding ? How do you avoid ? Size of given struct ?

__attribute__() and #define pragma pack(1)

Recursive struct declaration ?

Can we have union under union ?

How do you have structure pointer in it's own structure ?

Array of structures ? passings struct into a function ?

Find out the offset of given struct member, when u have no pointer to that struct ?

POINTERS:

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Applications of pointer ? Speciality of pointer ?

Pointer addition/deletion.

Allocate memory to pointer ?

typecasting pointers ?

Pointer to single,two,three dimensional arrays ? memory allocate ?

pointer with const qualifier ? conts int *a, int *const a diff ?

A function which defines a 2D array and return pointer, The caller able to get the address and can access it. Write a program.

Size of pointer ?

What is FILE pointer ? How it's being used ?

What is NULL pointer ? void pointer ?

Difference Questions 

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Diff btw enum constant and #define const ?

Diff btw inline func and #define func ?

Diff btw #ifdef and #if define ?

Diff btw char const and string const ?

Diff btw declaration and definitions ?

Diff btw #include "" and <> ?

Diff btw auto,static,reg,extern ?

Diff btw malloc,calloc ?

Diff btw pointers and arrays ?

DATA STRUCTURES:

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[STACK,QUEUE,LINKEDLIST,HASHING,BINARYTREE,SEARCH,SORTING]

Stack [implement using LL,array]

    Push,Pop,Peep,

Queue [implement using LL,array]

    Insert,Delete,

Circular Queue[using LL and array]

    Add/Delete/Searching/

Priority Queue[Arrays, LL]

    Add/Delete

Linked List:- Single/double

    Addition,Deletion - (start,end,middle,nth position,count)

    [ascend/descend order] copy LL, Delete LL, Append 2 LL

    reverse,recursive_Reverse,Sorting,concat2list,remove duplicates,

    delete_current_node(no head pointer available)

    insert/delete n th element from last.

    How do you convert doubly linked list to single without using

    structures?

    In which data structure, elements can be added or removed at

    either end, but not in the middle? Dequeue

    Find out the character that repeats itself in a big arrays[1000

    characters in it]

    What is the most efficient way of finding a loop in linklist.

    Add element in the middle of LL with single traversal.

Binary Tree

    Add/Delete/print(inorder,preorder,postorder)

    Application/ -Arithmetic Expresssion, SymbolTable

    construction,Syntax analysis.

    What is No of nodes/depth/size of tree relations.

AVL Tree

    Add/Delete/

    Application

Searching

    Linear,Divide&conquer,BinarySearch

Sorting

    Bubble,Selection,Quick,Merge,

HASH - Addition/Deletion/Applications.