https://github.com/mrkem598/c-interview-q-a
:question::white_check_mark:An interview questions for C language! Computer algorithm and design!
https://github.com/mrkem598/c-interview-q-a
c c-language computer-algorithms interview question-answering
Last synced: 10 months ago
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:question::white_check_mark:An interview questions for C language! Computer algorithm and design!
- Host: GitHub
- URL: https://github.com/mrkem598/c-interview-q-a
- Owner: mrkem598
- License: mit
- Created: 2017-08-21T12:48:42.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2017-10-10T01:37:27.000Z (over 8 years ago)
- Last Synced: 2025-04-11T17:17:04.850Z (about 1 year ago)
- Topics: c, c-language, computer-algorithms, interview, question-answering
- Homepage: https://mrkem598.github.io/C-interview-q-a/
- Size: 19.5 KB
- Stars: 4
- Watchers: 0
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
***
# C Language Interview Questions and Answer
***
***
### This interview questions for C language is in it's infantile stage and any contribution is welcome!
:school::blue_book::book:Do not expect advanced content here since I am doing this while I am learning it!!!
***
## 1. What does `#include` represent in c lan?
Answer: It is a statment which tells the compiler to insert the contents of `stdio(standard input out put)` at the particular place. This is a pre-processor directive. It is not part of our program, it is an instruction to the compiler to make it do something.
It is the pre-processor that is part of the compiler which actually gets your program from the file.
It tells the compiler to inlcude the contents of a file, in this case the system file `stdio.h`.
***
## 2. `< >` means in ``?
Answer: The compiler knows it's a system file and therefor must be looked for in a special place, by the fact that the name is enclosed in `< >`.
***
## 3. `stdio` means?
Answer: It stands for standard input output because
:white_check_mark:`printf()` is a Standard Output function.
:white_check_mark:`scanf()` is a Standard Input function.
In short, if we want to use `printf()` in a programme then , we need to include `stdio` header file.
***
## 4. If I want to use `getch()`, `clrscr()` etc.. what do I need to include in the header file?
Answer: We need to include `conio` in a header file and similarly if we are using square root function `sqrt()` we need to include `math` in a header file.
***
## 5. Write a function in C language to generate a prime numbers below 100?
Answer:
```
#include
#include
main(){
int this_number, divisor, not_prime;
this_number = 3;
while(this_number < 100){
divisor = this_number / 2;
not_prime = 0;
while(divisor > 1) {
if(this_number % divisor == 0) {
not_prime = 1;
divisor = 0;
}
else
divisor = divisor-1;
}
if(not_prime == 0)
printf("%d is a prime number\n", this_number);
this_number = this_number + 1;
}
exit(EXIT_SUCCESS);
}
```
```
Answer:
3 is a prime number
5 is a prime number
7 is a prime number
11 is a prime number
13 is a prime number
17 is a prime number
19 is a prime number
23 is a prime number
29 is a prime number
31 is a prime number
37 is a prime number
41 is a prime number
43 is a prime number
47 is a prime number
53 is a prime number
59 is a prime number
61 is a prime number
67 is a prime number
71 is a prime number
73 is a prime number
79 is a prime number
83 is a prime number
89 is a prime number
97 is a prime number
```
***
## 6. write a program that prints prime pairs — a pair of prime numbers that differ by 2, for example 11 and 13, 29 and 31?
Answer:
```
#include
#include
main(){
int this_number, divisor, not_prime;
int last_prime;
this_number = 3;
last_prime = 3;
printf("1, 3 is a prime pair\n");
while(this_number < 100){
divisor = this_number / 2;
not_prime = 0;
while(divisor > 1){
if(this_number % divisor == 0){
not_prime = 1;
divisor = 0;
}
else
divisor = divisor-1;
}
if(not_prime == 0){
if(this_number == last_prime+2)
printf("%d, %d is a prime pair\n",
last_prime, this_number);
last_prime = this_number;
}
this_number = this_number + 1;
}
exit(EXIT_SUCCESS);
}
```
```
1, 3 is a prime pair
3, 5 is a prime pair
5, 7 is a prime pair
11, 13 is a prime pair
17, 19 is a prime pair
29, 31 is a prime pair
41, 43 is a prime pair
59, 61 is a prime pair
71, 73 is a prime pair
```
***
## 7. How to add comment in C language?
Answer: We can add comment by using /*..........*/ in C language.
***
## 8. Write variable naming rules?
Answer:
- name can be any combination of upper and lower case letters(a-z, A-Z), digits(0-9), and the character _ No other characters can be used in a variable name.
- name must start with a letter
- blanks are not allowed
- Upper and lower case are allowed e.g. NUMBER , Number, number, nuMBER are all different.
- should be descriptive (name need to describe the the information that the variable holds)
- no restriction on the length of variables but make it short and precise
- names cannot be reserved words e.g float, this,...
acceptable e.g. a, b, c, C, SUM, sum, Count, value, Number, x_dot, Salary, Value1, dhgfhL
not acceptable e.g. 1ab
inte rest
Ca$h
Amount-of-loan (- not allowed)
int (reserved word)
***
## 9. OR is a binary operator and is denoted bu the symbol ||, which is two adjacent pipe symbols. What does `(x || y)` mean?
Answer: The possible output for `(x || Y)` is gonna be true or y is true or both are true.
***
## 10. Why is termination an important characteristic of an algorithm?
Answer:
If we started following an algorithm that did not terminate, we would never finish executing it!
***
## 11. Why is clarity an important characteristic of an algorithm?
Answer:
While executing a step, we should know exactly what must be done. If we did not, then there would be no single specific outcome for a particular step. Another good reason is that algorithms are usually translated into computer programs, and computer programs do not leave room for ambiguity.
***
## 12. Give one example of a variable of each of the following data types:
integers
floating numbers
characters
Booleans
Answer:
These answers are representative of each of the data types.
integers: number of windows in a room, number of words in a memory, or the rounded-off value of the temperature (negative numbers are integers too), and so on
floating numbers: the cost of an item in a store, the precise temperature, and so on
characters: the four directions specified by 'N', 'S', 'E', or 'W', one's letter grade in a class, or gender ('F' or 'M')
Booleans: the answer to the questions, "Are you female?" or "Do you wish to contribute to the XYZ fund?"
***
## 13. Evaluate the results of the following expressions, given the following values for these variables:
x = true, y = true, z = false
x && y || z
!x && y || z
```
Answer:
a. true. This expression is interpreted as
(x && y) || z
(true && true) || false
(true) || false
true
```
```
b. false. This expression is interpreted as
((!x) && y) || z
((!true) && true) || false
(false && true) || false
false || false
false
```
***
## 14. Evaluate the results of the following expressions, given the following initial values:
```
x = 23, y = –10, z = 12
A. x % z
B. x + y*z
C. x/y*z
D. z % z
```
Answer:
```
A. 11
x % z
23 % 12
23/12 = 1 with a remainder of 11
```
```
B. –97
The expression is interpreted as
x + (y * z)
23 + (–10 x 12)
23 + (–120)
–97
```
C. –27.6
x / y * z
23/–10 x 12 (remember that / and * are left associative)
–2.3 x 12
–27.6
```
D. 0
z % z
12 % 12
12/12 = 1 with a remainder of 0
```
***
## 15. Starting with the following initial values, specify the value of each variable at the end of each step, in the following pseudocode.
```
x = 10, y = 20, z = 30
Set x = x + 20
Set y = y * x
Set y = y % z + x
Set z = z – 20
Set z = z ^ 3 ^ 2
```
Answer:
***
## 16. Determine the total number of bits in a memory whose size is specified as 100MB X 32.
Answer
Remember that "B" stands for "byte" (8 bits). So,
100 MB = 100 * 220 * 8 bits
= 100 * 1,048,576 * 8 bits
Thus the 100 MB X 32 memory will contain 100 * 1,048,576 * 8 * 32 or 26,843,545,600 bits.
***
## 17. When a variable has just been declared, what initial value does it contain?
Answer:
No proper initial value exists. Using an uninitialized variable will invariably lead to run-time errors.
***
## 18. What is the difference between: (a) x == y and (b) x = y?
Answer:
The first, x == y, is a Boolean expression whose answer is always either true or false, whereas the second, x = y, is an assignment statement.
***
## 19. What is the difference between an expression and a statement?
Answer:
A statement is the basic unit of execution in a program.
Expressions are usually parts of statements. An expression is something that evaluates to a single valu
int num1, num2, sum;
sum = num1 + num2;
printf("\nEnter two number : ");
scanf("%d %d", num1,num2);
sum = num1 + num2;
printf("Sum : " sum);
return(o)
}
***
## 21. Write a C program to find area and circumference of a circle?
Answer:
```
#include
int main() {
int rad;
float PI = 3.14, area, ci;
printf("\nEnter your radius : ");
scanf("%d", &rad);
area = PI * rad * rad;
printf("\nArea of the circle is : %f ", area);
ci = 2 * PI * rad;
printf("\nCircumference : %f ", ci);
return 0;
}
```
***
## 22. Create a program that can add up the number of coins(penny, nickle, dime, quarter);
Answer:
#include
int main() {
/*variable defination*/
int penny, nickle, dime, quarter;
float coinTotal;
/*prompt for input*/
printf("\nEnter the number of penny : ");
scanf("%d", &penny);
printf("\nEnter the number of nickle you have : ");
scanf("%d", &nickle);
printf("\nEnter the number of dime you have : ");
scanf("%d", &dime);
printf("\nEnter the number of quarter you have : ");
scanf("%d", &quarter);
/*formula to add coin*/
coinTotal = (penny * 0.01) + (nickle * 0.50) + (dime * 0.10) + (quarter * 0.25);
/*print out the total*/
printf("\nThe total coint you entered is : %f", coinTotal);
return 0;
}
## 22. Calculate the perimeter of the triangle? And explain your program in detail?
Answer:
I have written, the C code for calculating the perimeter of the triangle as follow. I have used float point to inter the sides of the triangle and the base. The perimeter will be a float number.
***
## 23. What is this line of code doing? scanf(“%f”, &height);
Answer:The scanf get value from stdin and put in variables named. This line of code is where we can input the height from the user. The letter f stands for inputting a float number and if we want to input integers we can simply change it to %d.
***
## 23. Write a program to calculate the gross salary of a person?
Answer:
```
#include
int main() {
int gross_salary, basic, da, ta;
printf("Enter basic salary : ");
scanf("%d", &basic);
da = (10 * basic) / 100;
ta = (12 * basic) /100;
gross_salary = basic + da + ta;
printf("\nGross salary : %d", gross_salary);
return 0;
}
```
***
## 24. Using C program add two numbers, namely num1 and num2 to print out the result?
Answer:
%20{%0A%20%20%20%20%20%20%20%20int%20num;%0A%20%20%20%20%20%20%20%20printf()
int main () {
/* variable definition: */
int value1,value2,value3,value4,value5,value6, value7,value8, value9,value10, sum;
/* Initialize sum */
sum = 0;
printf("Enter an Integer for value1\n");
scanf("%d", &value1);
printf("Enter an Integer for value2\n");
scanf("%d", &value2);
printf("Enter an Integer for value3\n");
scanf("%d", &value3);
printf("Enter an Integer for value4\n");
scanf("%d", &value4);
printf("Enter an Integer for value5\n");
scanf("%d", &value5);
printf("Enter an Integer for value6\n");
scanf("%d", &value6);
printf("Enter an Integer for value7\n");
scanf("%d", &value7);
printf("Enter an Integer for value8\n");
scanf("%d", &value8);
printf("Enter an Integer for value9\n");
scanf("%d", &value9);
printf("Enter an Integer for value10\n");
scanf("%d", &value10);
sum = value1 + value2 + value3 + value4 + value5 + value6 + value7 + value8 + value9 + value10;
printf("Sum is %d\n " , sum );
if (sum >100)
printf("Sum is over 100\n");
return 0;
}
```
***
## 26. Create a program to determin wheter you can drive or not by entering your age??
Solution:
```
// C code
// This program will ask your age and determin to drive nor not.
// Developer: Mohammed Kemal
// Date: Sep 24, 2017
#include
int main(){
//declaring variable
int age;
//prompt the user to enter age
printf("\nEnter your age to determin whether you can drive or not?");
while (scanf("%d", &age) !=EOF) {
// when the age below the cut point let them know they are to Young
if( age < 16 && age > 0)
{
printf("\nToo Young To Drive Car!");
// Otherwise let them know too old to drive or too young
}
else if( age > 80)
{
printf("\nToo old to drive car!");
}
else if (age < 0 )
{
printf("\nYou need to enter positive number!");
}
else
{
printf("\nYou can drive!");
}
printf("Enter another age, or CTRL Z to exit.\n\n");
}
return 0;
}
```