LinkedIn Skill Assessment – C (Programming Language)

Q1. Which Code sample will eventually cause the computer to run out of memory?

• [x] :

while(1)
{
    char *smallString = (char *) malloc(10);
}

• [ ] :

long long number = 1;
    while(1)
    number *= 2;

• [ ] :

while(1)
{
    char hugeString[1000000L];
    memset(hugeString, 0, 1000000L);
}

• [ ] :

while(1)
{
    long *bigArray = (long *) malloc(sizeof(long) * 1000);
    memset(bigArray, 1000000, 1000);
    free(bigArray);
}

Q2. What will this code print on the screen?

int f1 (int a, int b)
{
    if (a > b)
    {
        printf("A is greater than B\n");
        return 1;
    }
    else
    {
        printf("B is greater than A");
        return 0;
    }
}

main()
{
    if (f1(20,10) || f1(10,20))
        printf("C is fun!\n");
}

• [x] :

A is greater then B
C is fun!

• [ ] :

A is greater then B
B is greater then A
C is fun!

• [ ] :

A is greater then B
B is greater then A

• [ ] Nothing is printed on Screen

Q3. What is the name for calling a function inside the same function?

• [x] recursion
• [ ] subfunction
• [ ] inner call
• [ ] infinite loop

Q4. What does the declaration of variable c2 demonstrate?

main(){
    char c1 ='a';
    char c2 = c1+10;
}

• [x] character arithmetic
• [ ] undefined assignment
• [ ] type conversion
• [ ] invalid declaration

Q5. What is this declaration an example of?

struct s {
    int i;
    struct s *s1;
    struct s *s2;
};

• [x] a node
• [ ] a linked list
• [ ] a stack
• [ ] a binary tree

Q6. Header files are listed using the preprocessing directive #include, and can have one of the following formats: #include <fileA> or #include “fileB”. What is the difference between these two formats?

• [ ] The preprocessor will try to locate fileA in same directory as the source file, and the fileB in a predetermined directory path.
• [ ] The preprocessor will try to locate fileA in the fixed system directory. It will try to locate fileB in the directory path designated by the -I option added to the command line while compiling the source code.
• [ ] The file using the fileA syntax must be system files, of unlimited number; fileB must be a user file at a maximun of one per source file.
• [x] The preprocessor will try to locate fileA in a predetermined directory path. It will try to locate fileB in the same directory as the source file along with a custom directory path.

Q7. Using a for loop, how could you write a C code to count down from 10 to 1 and display each number on its own line?

• [ ] :

for (int i = 0; i>=0, i--){
    printf("%d\n", i);
}//end of loop

• [ ] :

int i;
for (i=1; i<=10; i++){
    printf("%d", i);
}

• [ ] :

int i = 10;
while (i>0){
    printf("%d\n", i);
    i--;
}

• [x] :

int i;
for (i= 10; i>0; i--){
    printf("%d\n", i);
}// end of loop

Q8. What is not one of the reserved words in standard C?

• [ ] volatile
• [x] typeof
• [ ] register
• [ ] typedef

Reference

Q9. What does the program shown below return?

int main(){
    int a=1, b=2, c=3, d=4;
    int x = a;
    if (a>b)
    if (b<c) x=b;
    else x=c;
    return(x);
}

• [x] 1
• [ ] 3
• [ ] 2
• [ ] 0

Q10. Using the Union declaration below, how many bytes of memory space will the data of this type occupy?

union Cars {
    char make[20];
    char model[30];
    short year;
} car;

• [ ] 32
• [ ] 54
• [x] 30
• [ ] 52

Q11. In this code sample, what is not a problem for C compiler?

main(){
    constant int PI = 3.14;
    printf("%f\n", pi);
}

• [x] The value of PI needs to be set to 3.141593, not 3.14
• [ ] The declaration of PI needs to say const, not constant.
• [ ] The data type of PI needs to be float not int.
• [ ] The printf statement needs to use PI, not pi.

Q12. Which is the smallest program to compile and run without errors?

• [ ] main()
• [ ] int main() {return 0;}
• [x] main() { }
• [ ] main() { ; }

Reference

Q13. What is optional in a function declaration?

• [ ] data type of parameters
• [ ] return type of function
• [x] parameter names
• [ ] number of parameters

Q14. C treats all devices, such as the display and the keyboard, as files. Which file opens automatically when a program executes?

• [x] stdout
• [ ] stdio.h
• [ ] default.h
• [ ] string.h

Q15. In which segment does dynamic memory allocation takes place?

• [ ] BSS Segment
• [ ] stack
• [x] heap
• [ ] data segment

Reference

Q16. Which function do you use to deallocate memory?

• [ ] dalloc()
• [ ] dealloc()
• [ ] release()
• [x] free()

Reference

Q17. In C language what are the basic building blocks that are constructed together to write a program?

• [ ] keywords
• [ ] identifiers
• [x] tokens
• [ ] functions

Q18. When is memory for a variable allocated?

• [ ] during the assigment of the variable
• [ ] during the initialization of the variable
• [x] during the declaration of the variable
• [ ] during the definition of the variable

Q19. C uses the call by value method to pass arguments to functions. How can you invoke the call by reference method?

• [x] by using pointers
• [ ] by declaring functions separately from defining them
• [ ] by using recursive functions
• [ ] by using global variables

Q20. A union allows you to store different ___ in the same ___.

• [ ] Objects; Structure
• [ ] Variables; Declaration
• [x] Data types; Memory space
• [ ] Arrays; Header file

Q21. What is the output of this program?

main() {
    char c1='a' , c2='A';
    int i=c2-c1;
    printf("%d", i);
}

• [ ] 32
• [ ] Runtime error
• [x] -32
• [ ] 0

Q22. What is the difference between scanf() and sscanf() functions?

• [ ] The scanf() function reads data formatted as a string; The sscanf() function reads string input from the screen.
• [x] The scanf() function reads formatted data from the keyboard; The sscanf() function reads formatted input from a string.
• [ ] The scanf() function reads string data from the keyboard; The sscanf() function reads string data from a string.
• [ ] The scanf() function reads formatted data from a file; The sscanf() function reads input from a selected string

Q23. What is not a valid command with this declaration?

char *string[20] = { "one", "two", "three"};

• [ ] printf("%c", string[1][2]);
• [x] printf("%s", string[1][2]);
• [ ] printf("%s", string[1]);
• [ ] printf(string[1]);

Q24. What is the expression player->name equivalent to?

• [ ] player.name
• [x] (*player).name
• [ ] *player.name
• [ ] player.*name

Q25. Which program will compile and run without errors?

• [ ] :

main() {
    for(i=0; i<10; i++) ;
}

• [x] :

main() {
int i=0;
    for(; i<10; i++) ;
}

• [ ] :

main() {
    int i;
    for(i=0; i<j; i++) ;
}

• [ ] :

main() {
int i;
    for (i= 10; i<10; i++)
}

Q26. What does this function call return?

1 main() { float x = f1(10, 5); }
2 float f1(int a, int b) { return (a/b); }

• [ ] 2
• [ ] 2.000000
• [ ] a runtime error
• [x] a compiler error

Q27. What does this program create?

#include <stdio.h>
int main() {
    int *p = NULL;
    return 0;
}

• [ ] a runtime error
• [x] a NULL pointer
• [ ] a compile error
• [ ] a void pointer

Q28. What is an alternative way to write the expression (*x).y?

• [ ] There is no equivalent.
• [x] x->y
• [ ] *x->y
• [ ] y->x

Q29. Compile time errors are static errors that can be found where in the code?

• [x] in declarations and definitions
• [ ] in functions and expressions
• [ ] in syntax and semantics
• [ ] in objects and statements

Q30. File input and output (I/O) in C is heavily based on the way it is done ___?

• [x] in Unix
• [ ] in C++
• [ ] in C#
• [ ] in DOS

Q31. What does the strcmp(str1, str2); function return?

• [x] 0 if str1 and str2 are the same, a negative number if str1 is less than str2, a positive number if str1 is greater than str2
• [ ] true (1) if str1 and str2 are the same, false (0) if str1 and str2 are not the same
• [ ] true (1) if str1 and str2 are the same, NULL if str1 and str2 are not the same
• [ ] 0 if str1 and str2 are the same, a negative number if str2 is less than str1, a positive number if str2 is greater than str1

Q32. What is the output of this program?

int a=10, b=20;
int f1(a) { return(a*b); }
main() {
printf("%d", f1(5));
}

• [x] 100
• [ ] 200
• [ ] 5
• [ ] 50

Q33. Which is not a correct way to declare a string variable?

• [ ] char *string = "Hello World";
• [x] char string = "Hello World";
• [ ] char string[20] = {'H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd'};
• [ ] char string[] = "Hello World";

Q34. Which choice is an include guard for the header file mylib.h?

• [ ] :

#ifdef MYLIB_H
#undef MYLIB_H

// mylib.h content

#endif /* MYLIB_H */

• [x] :

#ifndef MYLIB_H
#define MYLIB_H

// mylib.h content

#endif /* MYLIB_H */

• [ ] :

#define MYLIB_H
#include "mylib.h"

#undef MYLIB_H

• [ ] :

#ifdef MYLIB_H
#define MYLIB_H

// mylib.h content

#endif /* MYLIB_H */

Q35. How many times does the code inside the while loop get executed in this program?

main(){
 int x=1;
 while(x++<100){
    x*=x;
    if(x<10) continue;
    if(x>50) break;
 }
}

• [ ] 100
• [x] 3
• [ ] 5
• [ ] 50

Q36. File input and output (I/O) in C is done through what?

• [ ] syntax-driven components
• [ ] native interfaces
• [ ] system objects
• [x] function calls

Q37. Directives are translated by the?

• [x] Pre-processor
• [ ] Compiler
• [ ] Linker
• [ ] Editor

Q38. The main loop structures in C programming are the for loop, the while loop, and which other loop?

• [x] do…while
• [ ] for…in
• [ ] repeat…until
• [ ] do…until

Q39. By default, C Functions are what type of functions?

• [ ] global
• [ ] static
• [x] library
• [ ] system

Q40. You have written a function that you want to include as a member of structure a. How is such as structure member defiened?

• [x] :

struct a {
    void *f1;
};

• [ ] :

struct a {
    void (*f1)();
};

• [ ] :

struct a {
    *(void *f1)();
};

• [ ] :

struct a {
    void *f1();
};

Q41. A Stack data structure allows all data operations at one end only, making it what kind of an implementation?

• [ ] FIFO
• [x] LIFO
• [ ] LILO
• [ ] LOLI

Q42. What does this program display?

main(){
    char *p = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    int i;
    for (i=0;i<5;i++) *p++; *p++;
    printf("%c",*p++);
}

• [ ] K
• [ ] M
• [ ] H
• [x] G

Q43. Describe the relationship between lvalue and rvalue.

• [ ] An lvalue may appear only on the left-hand side of an assignment; an rvalue may appear only on the right-hand side.
• [ ] An lvalue may appear only on the left-hand side of an assignment; an rvalue may appear on either the left-hand or right-hand side.
• [ ] An lvalue and an rvalue may appear on either left-hand or right-hand side of an assignment.
• [x] An lvalue may appear on the left-hand or right-hand side of an assignment; an rvalue may appear only on the right-hand side.

Q44. Which operator is used to access the address of a variable?

• [ ] %
• [ ] **
• [ ] *
• [x] &

Q45. Which add function properly returns the updated value of result?

• [x] :

void add (int a, int b, int *result)
{
    *result = a+b;
}

main()
{
    int a = 10;
    int b = 20;
    int result = 0;

    add(a,b,&result);
}

• [ ] :

void add (int a, int b, int result)
{
    result = a+b;
}

main()
{
    int a = 10;
    int b = 20;
    int result = 0;

    add(a,b,result);
}

• [ ] :

void add (int a, int b, int *result)
{
    result = a+b;
}

main()
{
    int a = 10;
    int b = 20;
    int result = 0;

    add(a,b,result);
}

• [ ] :

void add (int *a, int *b, int *result)
{
    result = a+b;
}

main()
{
    int a = 10;
    int b = 20;
    int result = 0;

    add(*a,*b,*result);
}

Q46. Consider the number of the Fibonacci series below 100: 0,1,1,2,3,5,8,13,21,34,55,89. Which piece of code outputs the sequence?

• [ ] :

void fibonacci(int a, int b)
{
    int c = a+b;

    if(a>100)
       return;

    printf("%d", a);

    fibonacci(a,b);
}

int main()
{
    fibonacci(0,1);
}

• [ ] :

void fibonacci(int a, int b)
{
    int c = a+b;

    if(a>100)
       return;

    printf("%d", b);

    fibonacci(a,c);
}

int main()
{
    fibonacci(0,1);
}

• [x] :

void fibonacci(int a, int b)
{
    int c = a+b;

    if(a>100)
       return;

    printf("%d", a);

    fibonacci(b,c);
}

int main()
{
    fibonacci(0,1);
}

• [ ] :

void fibonacci(int a, int b)
{
    int c = a+b;

    if(a>100)
       return;

    printf("%d", c);

    fibonacci(b,c);
}

int main()
{
    fibonacci(0,1);
}

Q47. Which is not a storage class specifier?

• [x] intern
• [ ] extern
• [ ] register
• [ ] static

Reference

Q48. Which line of code, after execution, results in i having the value of 1?

• [ ] for(i=1; i<=1; i++);
• [ ] for(i=1; i=10; i++);
• [x] for(i=1; i==10; i++);
• [ ] for(i=10; i>=1; i--);

Q49. What is the value of variable c at the end of this program?

1 main() {
2   int a, b, c;
3   a=10; b=50;
4   c=a * b % a;
5 }

• [ ] 50
• [ ] 5
• [x] 0
• [ ] 500

Q50. What is not one of the basic data types in C

• [ ] long double
• [ ] unsigned char
• [x] array
• [ ] float

Q51. What is the member access operator for a structure?

• [ ] ,
• [ ] []
• [x] .
• [ ] :

Q52. What standard data type provides the smallest storage size and can be used in computations?

• [x] char
• [ ] float
• [ ] int
• [ ] short

Q53. what does the ctype tolower() function do?

• [ ] It returns TRUE for lowercase letters of the alphabet.
• [ ] It ensures that text output uses only ASCII values (0 through 127).
• [ ] It returns FALSE for lowercase letters of the alphabet.
• [x] It converts an uppercase letter of the alphabet to lowercase.

Q54. Void pointer vptr is assigned the address of float variable g. What is a valid way to dereference vptr to assign its pointed value to a float variable named f later in the program?

float g;
void *vptr=&g;

• [ ] f=(float *)vptr;
• [x] f=*(float *)vptr;
• [ ] f=*(float)vptr;
• [ ] f=(float)*vptr;

Q55. The dynamic memory allocation functions are defined in which system header file ?

• [ ] stdio.h
• [x] stdlib.h
• [ ] limits.h
• [ ] stddef.h

Q56. A function is a set of _.

• [ ] declarations
• [x] statements
• [ ] variables
• [ ] objects

Q57. How are static functions different from global functions?

• [ ] Static functions must be declared in advance of being defined.
• [ ] Static functions must be declared is a separate header file.
• [ ] Static functions always return the same value.
• [x] Static functions can be accessed only in the file where they are declared.

Q58. Which code example creates the string “Hello Mars” in storage buffer hello.

• [ ] :

    char hello[25];
    strcpy(hello, "Hello ");
    strcpy(hello, "Mars");

• [x] :

    char hello[25];
    char *p;
    strcpy(hello, "Hello World");
    p = hello;
    p +=6;
    strcpy(p, "Mars");

• [ ] :

    char *hello;
    strcpy(hello, "Hello World");
    hello+=6;
    strcpy(hello, "Mars");

• [ ] :

    char hello[25];
    strcpy(hello, "Hello World");
    strcpy(*hello[6], "Mars");

Q59. If you use the fopen() function with the “a” mode, what happens if the named file doesn’t exist?

• [ ] The file is created and opened for reading.
• [x] The file is created and opened for writing.
• [ ] The fopen() function returns a NULL indicating that the operation has failed.
• [ ] The file is created and opened for both writing and reading

Reference

Q60. What does this function return?

int fl(int a, int b) { return(a>b?a:b); }

• [ ] compiler error
• [ ] the smaller value of the two passed parameters
• [ ] runtime error
• [x] the greater value of the two passed parameters

Q61. Which function fo you use to deallocate memory?

• [x] free()
• [ ] dealloc()
• [ ] release()
• [ ] dealloc()

Q62. Which option is a valid function name?

• [x] draw_star()
• [ ] 5times()
• [ ] upper-limit()
• [ ] auto()

Q63. What is not a valid type definition of a structure that contains x and y coordinates as integers, and that can be used as shown for the variable named point?

coord point;
point.x = 9;
point.y = 3;

• [ ] :

struct coord{
    int x;
    int y;
};
typedef struct coord coord;

• [x] :

typedef struct coord{
    int x;
    int y;
};

• [ ] :

typedef struct coord{
    int x;
    int y;
} coord;

• [ ] :

typedef struct{
    int x;
    int y;
} coord;