C-interview-q-a
:question::white_check_mark:An interview questions for C language! Computer algorithm and design!
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<stdio.h> 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 <stdio.h>?
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 <stdio.h>
#include <stdlib.h>
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 <stdio.h>
#include <stdlib.h>
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 + yz C. x/yz 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
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<stdio.h>
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:
<img width=”523” alt=”screen shot 2017-09-10 at 8 34 26 pm” src=”https://user-images.githubusercontent.com/23619819/3
***
Create a C program to Enter a number to see if it is an even or odd number?
Answer:
#include <stdio.h>
int main () {
int num;
printf("\nEnter a number to see if it is even or odd number? : ");
scanf("%d", &num);
if(num %2 == 0)
printf("%d is an even number.", num);
else printf("%d is an odd number.", num);
return (0);
}
25. Write a C code to add 10 numbers and if the vlaue greater than 100 say it’s greater than 100.
Answer:
/*The following is the C Code that will compile in execute in the online compilers.*/
/* C code
This program will calculate the sum of 10 integers.
Developer: Mohammed Kemal
Date: Sep 14, 2017 */
#include <stdio.h>
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 <stdio.h>
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;
}