C Language: Question Bank

material from hearing Mantra. Subscribe to thaw updates via email. corporeal from query Mantra. Subscribe to free updates via email. Favourite 50 C oppugn Question Bank for freshers and experienced IT chopinemers Written by Madhulika Reddy and Dhoka Ratan. redact and Published by Sridhar Jammalamadaka Get the latest updates and news on slide byics biography and Education from Interview Mantra Subscribe to Interview Mantra for free. ABOUT THIS BOOK This admit comprises of Interview Questions and Answers collected from the famous c atomic number 18er advice blog www. InterviewMantra. et The aim of this restrain is to help freshers and experienced course of instructionmemers to flyingly brush up the basic concepts of C language. This book send away be employd as a quick study guide before attending a job interview which requires knowledge of C programming language. The questions that appear in this book atomic number 18 few of the approximately frequently asked que stions in IT Job interviews in top MNC companies. All the questions grant been neatly answered and have been supported with example computer code wherever applicable. A lot of effort has been put into this book to trade name the answers as accurate as possible, still no warranty or fitness is implied.The authors and the publisher sh every last(predicate) have neither liability nor responsibility to either person or entity with respect to whatever loss or alter arising from the information contained in this book or from the use of the programs accompanying it. enjoy send your feedback to us via email to emailprotected net COPYRIGHT INFO C language Interview Question Bank by Sridhar Jammalamadaka is licensed at a lower place a Creative Commons Attribution-Sh atomic number 18 Alike 2. 5 India License. Based on a work at www. interviewmantra. net. In simple words, you may use this work for commercial purposes, remix the work, reproduce it by any means, provided ou keep a link to http//www. interviewmantra. net and attribute the work to the owner Sridhar Jammalamadaka. CONTENTS AT A GLANCE 1. 2. 3. 4. 5. Chapter Name pg-no Variables & Control carry . . . . . . . . . . . . . . . . . . . . 6 Operators, Constants & Structures . . . . . . . . . . . .11 Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Pointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 computer programmes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 Material from Interview Mantra. Subscribe to free updates via email. TABLE OF CONTENTSCHAPTER 1 Variables & Control Flow 1. What is the difference mingled with declaring a inconstant and delimitate a protean? 2. What is a tranquil varying quantity? 3. What is a read variable? 4. Where is an auto variable stored? 5. What is background signal & computer memory allocation of medical extern and international variables? 6. What is scope & retentivity allocation of read, static and topical anesthetic variables? 7. What are warehousing memory, inattention place, scope and sprightliness story of Automatic and testify storage dissever? 8. What are storage memory, default observe, scope and life of silent and External storage sectionalization? 9. What is the difference amongst break and continue averments? 0. What is the difference between for and while loops? CHAPTER 2 Operators, Constants & Structures 1. Which bitwise operator is suitable for blocking whether a particular bit is ON or OFF? 2. Which bitwise operator is suitable for turning OFF a particular bit in a number? 3. What is equivalent of multiplying an unsigned int by 2 left shift of number by 1 or right shift of number by 1? 4. What is an figuring Constant? 5. What is a expression? 6. What are the differences between a structure and a union? 7. What are the advantages of unions? 8. How can flakedef be to define a type of structure? 9. call for open a program that dete riorates 3 poetry from a be vast exploitation a structure. 10. In code clipping below struct Date int yr int mean solar day int month date1,date2 date1. yr = 2004 date1. day = 4 date1. month = 12 Write a incline that assigns determine to date2. Arguments to the function must be pointers to the structure, Date and integer variables date, month, year. Material from Interview Mantra. Subscribe to free updates via email. CHAPTER 3 Functions 1. What is the purpose of of import() function? 2. develop ascendency line arguments of main function? 3. What are header files? Are functions say or defined in header files ? 4.What are the differences between nominal arguments and actual arguments of a function? 5. What is pass by value in functions? 6. What is pass by reference in functions? 7. What are the differences between getchar() and scanf() functions for nurture strings? 8. Out of the functions fgets() and gets(), which one is safer to use and why? 9. What is the difference between the functions strdup() and strcpy()? CHAPTER 4 Pointers 1. What is a pointer in C? 2. What are the advantages of utilize pointers? 3. What are the differences between malloc() and calloc()? 4. How to use realloc() to dynamically increase size of an already allocated soldiers? . What is the equivalent pointer expression for referring an element aijkl, in a four dimensional set about? 6. Declare an array of three function pointers where each(prenominal) function receives two integers and returns float. 7. Explain the variable assignment in the declaration int *(*p10)(char *, char *) 8. What is the value of sizeof(a) /sizeof(char *) in a code clip char *a4=sridhar,raghava,shashi,srikanth 9. (i) What are the differences between the C statements below char *str = how-dye-do char arr = Hello (ii) Whether following statements get complied or non?Explain each statement. arr++ *(arr + 1) = s printf(%s,arr) CHAPTER 5 Programs 1. Write a program to go through factorial of the presumptuousness number. 2. Write a program to check whether the wedded number is even or odd. 3. Write a program to flip-flop two add up using a fugitive variable. 4. Write a program to swap two numbers without using a temporary variable. Material from Interview Mantra. Subscribe to free updates via email. 5. Write a program to swap two numbers using bitwise operators. 6. Write a program to dress the superior of three numbers. 7. Write a program to find the greatest among ten numbers. . Write a program to check whether the apt(p) number is a primeval. 9. Write a program to check whether the stipulation number is a palindromic number. 10. Write a program to check whether the given string is a palindrome. 11. Write a program to generate the Fibonacci series. 12. Write a program to print Hello World without using semicolon anyplace in the code. 13. Write a program to print a semicolon without using a semicolon anywhere in the code. 14. Write a program to analyze two strings without using strcmp() function. 15. Write a program to concatenate two strings without using strcat() function. 16.Write a program to delete a specified line from a text file. 17. Write a program to replace a specified line in a text file. 18. Write a program to find the number of lines in a text file. 19. Write a C program which asks the exploiter for a number between 1 to 9 and shows the number. If the user inputs a number out of the specified range, the program should show an error and trigger the user for a valid input. 20. Write a program to vaunt the multiplication table of a given number. Testimonials Anushka M says Thank you soooo over very much for all these questions, along with the solutions. Its a great compilation.Thanks a lot guys. Anonymous says Awesome. Thanks a ton for uploading this pdf, your concept was crystallizing clear. directly I am very confident nigh myself. Now Im ready to face the interview challenge. Thanks once again. Urmi says Thank You.. Its Nice.. It protected my valuable Time.. Thanks a lot Rajakumari says Thank you so much Mr. Sridhar. No words to say , lot of thanks Very helpful to freshers & experienced. Material from Interview Mantra. Subscribe to free updates via email. CHAPTER 1 Variables & Control Flow 1. What is the difference between declaring a variable and defining a variable?Declaration of a variable in C hints the compiling program about the type and size of the variable in compile time. Similarly, declaration of a function hints about type and size of function parameters. No aloofness is reserved in memory for any variable in example of declaration. sheath int a Here variable a is declared of data type int Defining a variable means declaring it and also allocating space to hold it. We can say Definition = Declaration + Space reservation. mannikin int a = 10 Here variable a is described as an int to the compiler and memory is allocated to hold value 10. 2. What is a static variable?A static v ariable is a special variable that is stored in the data segment unlike the default automatic variable that is stored in stack. A static variable can be initialized by using keyword static before variable name. Example static int a = 5 A static variable behaves in a contrary demeanor depending upon whether it is a global variable or a topical anesthetic variable. A static global variable is similar as an ordinary global variable except that it cannot be accessed by other files in the same program / project even with the use of keyword extern. A static local variable is different from local variable.It is initialized only once no consider how umpteen times that function in which it resides is called. It may be use as a count variable. Example include //program in file f1. c void count(void) static int count1 = 0 int count2 = 0 count1++ count2++ printf( respect of count1 is %d, Value of count2 is %d, count1, count2) /*Main function*/ int main() count() count() count() return 0 yield Value of count1 is 1, Value of count2 is 1 Value of count1 is 2, Value of count2 is 1 Material from Interview Mantra. Subscribe to free updates via email. Value of count1 is 3, Value of count2 is 1 3. What is a put down variable?Register variables are stored in the mainframe computer registers. Its default value is a garbage value. mise en scene of a register variable is local to the engorge in which it is defined. Lifetime is gutter assure be within the obturate in which the register variable is defined. Variable stored in a CPU register can always be accessed instant(prenominal) than the one that is stored in memory. Therefore, if a variable is utilise at many places in a program, it is better to declare its storage categorise as register Example register int x=5 Variables for loop counters can be declared as register. Note that register keyword may be ignored by some compilers. . Where is an auto variables stored? Main memory and CPU registers are the two memo ry locations where auto variables are stored. Auto variables are defined under automatic storage class. They are stored in main memory. Memory is allocated to an automatic variable when the cube which contains it is called and it is de-allocated at the completion of its block execution. Auto variables Storage main memory. neglectfulness value garbage value. Scope local to the block in which the variable is defined. Lifetime till the control remains within the block in which the variable is defined. 5.What is scope & storage allocation of extern and global variables? Extern variables belong to the External storage class and are stored in the main memory. extern is utilize when we have to refer a function or variable that is implemented in other file in the same project. The scope of the extern variables is Global. Example /*************** Index f1. c ****************/ include extern int x int main() printf(value of x %d, x) return 0 Index f2. c ****************/ int x = 3 He re, the program written in file f1. c has the main function and reference to variable x. The file f2. c has the declaration of variable x.The compiler should know the datatype of x and this is done by extern definition. Material from Interview Mantra. Subscribe to free updates via email. Global variables are variables which are declared preceding(prenominal) the main( ) function. These variables are accessible throughout the program. They can be accessed by all the functions in the program. Their default value is zero. Example include int x = 0 /* Variable x is a global variable. It can be accessed throughout the program */ void increment(void) x = x + 1 printf( value of x %d, x) int main() printf( value of x %d, x) increment() return 0 6.What is scope & storage allocation of register, static and local variables? Register variables belong to the register storage class and are stored in the CPU registers. The scope of the register variables is local to the block in which the vari ables are defined. The variables which are used for more number of times in a program are declared as register variables for faster access. Example loop counter variables. register int y=6 Static variables Memory is allocated at the beginning of the program execution and it is reallocated only after the program terminates.The scope of the static variables is local to the block in which the variables are defined. Example include void decrement() static int a=5 a printf(Value of a%d, a) int main() decrement() return 0 Here a is initialized only once. Every time this function is called, a does not get initialized. so output would be 4 3 2 etc. , Local variables are variables which are declared within any function or a block. They can be accessed only by function or block in which they are declared. Their default value is a garbage value. 7. What are storage memory, default value, scope and life of Automatic and Register storage class? . Automatic storage class Storage Default value main memory. garbage value. Material from Interview Mantra. Subscribe to free updates via email. Scope Lifetime Storage Default value Scope Lifetime local to the block in which the variable is defined. till control remains within the block. CPU registers. garbage value. local to the block in which the variable is defined. till control remains within the block. 2. Register storage class 8. What are storage memory, default value, scope and life of Static and External storage class? 1. Static storage class Storage Default value ScopeLifetime Storage Default value Scope Lifetime main memory. zero local to the block in which the variable is defined. till the value of the variable persists between different function calls. main memory zero global as long as the program execution doesnt come to an end. 2. External storage class 9. What is the difference between break and continue statements? Differences between break and continue statements break 1. break is a keyword used to terminate the loop or exit from the block. The control jumps to next statement after the loop or block. 2. Syntax description 1 Statement 2 Statement n break 3. reak can be used with for, while, do- while, and switch statements. When break is used in nested loops i. e. within the inner most loop then only the innermost loop is terminated. 4. Example i = 1, j = 0 while(i a && b c) printf(b is Greater than a and c) else if (c a && c b) printf(c is Greater than a and b) else printf(all are equal or any two value are equal) return 0 Output Enter a,b,c 3 5 8 c is Greater than a and b definition with examples Consider three numbers a=5,b=4,c=8 if(ab && ac) then a is great than b and c now check this condition for the three numbers 5,4,8 i. . if(54 && 58) /* 54 is true but 58 fails */ so the control shifts to else if condition else if(ba && bc) then b is greater than a and c now checking this condition for 5,4,8 i. e. else if(45 && 48) /* both the conditions fail */ now t he control shifts to the next else if condition else if(ca && cb) then c is greater than a and b Material from Interview Mantra. Subscribe to free updates via email. now checking this condition for 5,4,8 i. e. else if(85 && 84) /* both conditions are satisfied */ Thus c is greater than a and b. 7.Write a program to find the greatest among ten numbers. Program include int main() int a10 int i int greatest printf(Enter ten values) // lay in 10 numbers in an array for (i = 0 i 10 i++) scanf(%d, i) //Assume that a0 is greatest greatest = a0 for (i = 0 i 10 i++) if (ai greatest) greatest = ai printf(Greatest of ten numbers is %d, greatest) return 0 Output Enter ten values 2 53 65 3 88 8 14 5 77 64 Greatest of ten numbers is 88 chronicle with example Entered values are 2, 53, 65, 3, 88, 8, 14, 5, 77, 64 They are stored in an array of size 10. et a be an array holding these values. /* how the greatest among ten numbers is found */ Let us consider a variable greatest. At the begi nning of the loop, variable greatest is assinged with the value of first element in the array greatest=a0. Here variable greatest is assigned 2 as a0=2. down the stairs loop is executed until end of the array a. for(i=0 igreatest) greatest= ai For each value of i, value of ai is compared with value of variable greatest. If any value greater than the value of greatest is encountered, it would be replaced by ai.After completion of for loop, the value of variable greatest holds the greatest number in the array. In this case 88 is the greatest of all the numbers. Material from Interview Mantra. Subscribe to free updates via email. 8. Write a program to check whether the given number is a prime. A prime number is a natural number that has only one and itself as factors. Examples 2, 3, 13 are prime numbers. Program include main() int n, i, c = 0 printf(Enter any number n ) scanf(%d, ) /*logic*/ for (i = 1 i