Spotify Technology Most Frequently Asked C Language Interview Questions Answers
What is wrong with this statement? myName = “Robin”;
You cannot use the = sign to assign values to a string variable. Instead, use the strcpy function. The correct statement would be: strcpy(myName, “Robin”);
How do you determine the length of a string value that was stored in a variable?
To get the length of a string value, use the function strlen(). For example, if you have a variable named FullName, you can get the length of the stored string value by using this statement: I = strlen(FullName); the variable I will now have the character length of the string value.
Is it possible to initialize a variable at the time it was declared?
Yes, you don’t have to write a separate assignment statement after the variable declaration, unless you plan to change it later on. For example: char planet[15] = “Earth”; does two things: it declares a string variable named planet, then initializes it with the value “Earth”.
Why is C language being considered a middle level language?
This is because C language is rich in features that make it behave like a high level language while at the same time can interact with hardware using low level methods. The use of a well structured approach to programming, coupled with English-like words used in functions, makes it act as a high level language. On the other hand, C can directly access memory structures similar to assembly language routines.
What are the different file extensions involved when programming in C?
Source codes in C are saved with .C file extension. Header files or library files have the .H file extension. Every time a program source code is successfully compiled, it creates an .OBJ object file, and an executable .EXE file.
What are reserved words?
Reserved words are words that are part of the standard C language library. This means that reserved words have special meaning and therefore cannot be used for purposes other than what it is originally intended for. Examples of reserved words are int, void, and return.
What are linked list?
A linked list is composed of nodes that are connected with another. In C programming, linked lists are created using pointers. Using linked lists is one efficient way of utilizing memory for storage.
What is FIFO?
In C programming, there is a data structure known as queue. In this structure, data is stored and accessed using FIFO format, or First-In-First-Out. A queue represents a line wherein the first data that was stored will be the first one that is accessible as well.
What is the significance of an algorithm to C programming?
Before a program can be written, an algorithm has to be created first. An algorithm provides a step by step procedure on how a solution can be derived. It also acts as a blueprint on how a program will start and end, including what process and computations are involved.
What is the advantage of an array over individual variables?
When storing multiple related data, it is a good idea to use arrays. This is because arrays are named using only 1 word followed by an element number. For example: to store the 10 test results of 1 student, one can use 10 different variable names (grade1, grade2, grade3… grade10). With arrays, only 1 name is used, the rest are accessible through the index name (grade[0], grade[1], grade[2]… grade[9]).
Write a loop statement that will show the following output:
1
12
123
1234
12345
Answer:
for (a=1; a<=5; i++) {
for (b=1; b<=a; b++)
printf("%d",b);
printf("\n");
}
What is wrong in this statement? scanf(“%d”,whatnumber);
An ampersand & symbol must be placed before the variable name whatnumber. Placing & means whatever integer value is entered by the user is stored at the “address” of the variable name. This is a common mistake for programmers, often leading to logical errors.
How do you generate random numbers in C?
Random numbers are generated in C using the rand() command. For example: anyNum = rand() will generate any integer number beginning from 0, assuming that anyNum is a variable of type integer.
What could possibly be the problem if a valid function name such as tolower() is being reported by the C compiler as undefined?
The most probable reason behind this error is that the header file for that function was not indicated at the top of the program. Header files contain the definition and prototype for functions and commands used in a C program. In the case of “tolower()”, the code “#include <ctype.h>” must be present at the beginning of the program.
What are comments and how do you insert it in a C program?
Comments are a great way to put some remarks or description in a program. It can serves as a reminder on what the program is all about, or a description on why a certain code or function was placed there in the first place. Comments begin with /* and ended by */ characters. Comments can be a single line, or can even span several lines. It can be placed anywhere in the program.
What is debugging?
Debugging is the process of identifying errors within a program. During program compilation, errors that are found will stop the program from executing completely. At this state, the programmer would look into the possible portions where the error occurred. Debugging ensures the removal of errors, and plays an important role in ensuring that the expected program output is met.
What are binary trees?
Binary trees are actually an extension of the concept of linked lists. A binary tree has two pointers, a left one and a right one. Each side can further branch to form additional nodes, which each node having two pointers as well.
Not all reserved words are written in lowercase. TRUE or FALSE?
FALSE. All reserved words must be written in lowercase; otherwise the C compiler would interpret this as unidentified and invalid.
What is the difference between the expression “++a” and “a++”?
In the first expression, the increment would happen first on variable a, and the resulting value will be the one to be used. This is also known as a prefix increment. In the second expression, the current value of variable a would the one to be used in an operation, before the value of a itself is incremented. This is also known as postfix increment.
What would happen to X in this expression: X += 15; (assuming the value of X is 5)
X +=15 is a short method of writing X = X + 15, so if the initial value of X is 5, then 5 + 15 = 20.
In C language, the variables NAME, name, and Name are all the same. TRUE or FALSE?
FALSE. C language is a case sensitive language. Therefore, NAME, name and Name are three uniquely different variables.
What is an endless loop?
An endless loop can mean two things. One is that it was designed to loop continuously until the condition within the loop is met, after which a break function would cause the program to step out of the loop. Another idea of an endless loop is when an incorrect loop condition was written, causing the loop to run erroneously forever. Endless loops are oftentimes referred to as infinite loops.
What is a program flowchart and how does it help in writing a program?
A flowchart provides a visual representation of the step by step procedure towards solving a given problem. Flowcharts are made of symbols, with each symbol in the form of different shapes. Each shape may represent a particular entity within the entire program structure, such as a process, a condition, or even an input/output phase.
What is wrong with this program statement? void = 10;
The word void is a reserved word in C language. You cannot use reserved words as a user-defined variable.
Is this program statement valid? INT = 10.50;
Assuming that INT is a variable of type float, this statement is valid. One may think that INT is a reserved word and must not be used for other purposes. However, recall that reserved words are express in lowercase, so the C compiler will not interpret this as a reserved word.
Write a program to print factorial of given number without using recursion?
#include<stdio.h>
#include<conio.h>
void main(){
int i,fact=1,number;
clrscr();
printf("Enter a number: ");
scanf("%d",&number);
for(i=1;i<=number;i++){
fact=fact*i;
}
printf("Factorial of %d is: %d",number,fact);
getch();
}
Write a program to print factorial of given number using recursion?
#include<stdio.h>
#include<conio.h>
long factorial(int n) // function to calculate the factorial of a given number.
{
if (n == 0)
return 1;
else
return(n * factorial(n-1)); //calling the function recursively.
}
void main()
{
int number; //declaration of variables.
long fact;
clrscr();
printf("Enter a number: ");
scanf("%d", &number);
fact = factorial(number); //calling a function.
printf("Factorial of %d is %ld\n", number, fact);
getch(); //It reads a character from the keyword.
}
What are actual arguments?
When you create and use functions that need to perform an action on some given values, you need to pass these given values to that function. The values that are being passed into the called function are referred to as actual arguments.
What is a newline escape sequence?
A newline escape sequence is represented by the \n character. This is used to insert a new line when displaying data in the output screen. More spaces can be added by inserting more \n characters. For example, \n\n would insert two spaces. A newline escape sequence can be placed before the actual output expression or after.
What is output redirection?
It is the process of transferring data to an alternative output source other than the display screen. Output redirection allows a program to have its output saved to a file. For example, if you have a program named COMPUTE, typing this on the command line as COMPUTE >DATA can accept input from the user, perform certain computations, then have the output redirected to a file named DATA, instead of showing it on the screen.
What are run-time errors?
These are errors that occur while the program is being executed. One common instance wherein run-time errors can happen is when you are trying to divide a number by zero. When run-time errors occur, program execution will pause, showing which program line caused the error.
What are structure types in C?
Structure types are primarily used to store records. A record is made up of related fields. This makes it easier to organize a group of related data.
What is wrong with this statement? myName = “Robin”;
You cannot use the = sign to assign values to a string variable. Instead, use the strcpy function. The correct statement would be: strcpy(myName, “Robin”);
How do you determine the length of a string value that was stored in a variable?
To get the length of a string value, use the function strlen(). For example, if you have a variable named FullName, you can get the length of the stored string value by using this statement: I = strlen(FullName); the variable I will now have the character length of the string value.
Is it possible to initialize a variable at the time it was declared?
Yes, you don’t have to write a separate assignment statement after the variable declaration, unless you plan to change it later on. For example: char planet[15] = “Earth”; does two things: it declares a string variable named planet, then initializes it with the value “Earth”.
Why is C language being considered a middle level language?
This is because C language is rich in features that make it behave like a high level language while at the same time can interact with hardware using low level methods. The use of a well structured approach to programming, coupled with English-like words used in functions, makes it act as a high level language. On the other hand, C can directly access memory structures similar to assembly language routines.
What are the different file extensions involved when programming in C?
Source codes in C are saved with .C file extension. Header files or library files have the .H file extension. Every time a program source code is successfully compiled, it creates an .OBJ object file, and an executable .EXE file.
What are reserved words?
Reserved words are words that are part of the standard C language library. This means that reserved words have special meaning and therefore cannot be used for purposes other than what it is originally intended for. Examples of reserved words are int, void, and return.
What are linked list?
A linked list is composed of nodes that are connected with another. In C programming, linked lists are created using pointers. Using linked lists is one efficient way of utilizing memory for storage.
What is FIFO?
In C programming, there is a data structure known as queue. In this structure, data is stored and accessed using FIFO format, or First-In-First-Out. A queue represents a line wherein the first data that was stored will be the first one that is accessible as well.
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| Spotify Technology Most Frequently Asked C Language Interview Questions Answers |
What is the significance of an algorithm to C programming?
Before a program can be written, an algorithm has to be created first. An algorithm provides a step by step procedure on how a solution can be derived. It also acts as a blueprint on how a program will start and end, including what process and computations are involved.
What is the advantage of an array over individual variables?
When storing multiple related data, it is a good idea to use arrays. This is because arrays are named using only 1 word followed by an element number. For example: to store the 10 test results of 1 student, one can use 10 different variable names (grade1, grade2, grade3… grade10). With arrays, only 1 name is used, the rest are accessible through the index name (grade[0], grade[1], grade[2]… grade[9]).
Write a loop statement that will show the following output:
1
12
123
1234
12345
Answer:
for (a=1; a<=5; i++) {
for (b=1; b<=a; b++)
printf("%d",b);
printf("\n");
}
What is wrong in this statement? scanf(“%d”,whatnumber);
An ampersand & symbol must be placed before the variable name whatnumber. Placing & means whatever integer value is entered by the user is stored at the “address” of the variable name. This is a common mistake for programmers, often leading to logical errors.
How do you generate random numbers in C?
Random numbers are generated in C using the rand() command. For example: anyNum = rand() will generate any integer number beginning from 0, assuming that anyNum is a variable of type integer.
What could possibly be the problem if a valid function name such as tolower() is being reported by the C compiler as undefined?
The most probable reason behind this error is that the header file for that function was not indicated at the top of the program. Header files contain the definition and prototype for functions and commands used in a C program. In the case of “tolower()”, the code “#include <ctype.h>” must be present at the beginning of the program.
What are comments and how do you insert it in a C program?
Comments are a great way to put some remarks or description in a program. It can serves as a reminder on what the program is all about, or a description on why a certain code or function was placed there in the first place. Comments begin with /* and ended by */ characters. Comments can be a single line, or can even span several lines. It can be placed anywhere in the program.
What is debugging?
Debugging is the process of identifying errors within a program. During program compilation, errors that are found will stop the program from executing completely. At this state, the programmer would look into the possible portions where the error occurred. Debugging ensures the removal of errors, and plays an important role in ensuring that the expected program output is met.
What are binary trees?
Binary trees are actually an extension of the concept of linked lists. A binary tree has two pointers, a left one and a right one. Each side can further branch to form additional nodes, which each node having two pointers as well.
Not all reserved words are written in lowercase. TRUE or FALSE?
FALSE. All reserved words must be written in lowercase; otherwise the C compiler would interpret this as unidentified and invalid.
What is the difference between the expression “++a” and “a++”?
In the first expression, the increment would happen first on variable a, and the resulting value will be the one to be used. This is also known as a prefix increment. In the second expression, the current value of variable a would the one to be used in an operation, before the value of a itself is incremented. This is also known as postfix increment.
What would happen to X in this expression: X += 15; (assuming the value of X is 5)
X +=15 is a short method of writing X = X + 15, so if the initial value of X is 5, then 5 + 15 = 20.
In C language, the variables NAME, name, and Name are all the same. TRUE or FALSE?
FALSE. C language is a case sensitive language. Therefore, NAME, name and Name are three uniquely different variables.
What is an endless loop?
An endless loop can mean two things. One is that it was designed to loop continuously until the condition within the loop is met, after which a break function would cause the program to step out of the loop. Another idea of an endless loop is when an incorrect loop condition was written, causing the loop to run erroneously forever. Endless loops are oftentimes referred to as infinite loops.
What is a program flowchart and how does it help in writing a program?
A flowchart provides a visual representation of the step by step procedure towards solving a given problem. Flowcharts are made of symbols, with each symbol in the form of different shapes. Each shape may represent a particular entity within the entire program structure, such as a process, a condition, or even an input/output phase.
What is wrong with this program statement? void = 10;
The word void is a reserved word in C language. You cannot use reserved words as a user-defined variable.
Is this program statement valid? INT = 10.50;
Assuming that INT is a variable of type float, this statement is valid. One may think that INT is a reserved word and must not be used for other purposes. However, recall that reserved words are express in lowercase, so the C compiler will not interpret this as a reserved word.
Write a program to print factorial of given number without using recursion?
#include<stdio.h>
#include<conio.h>
void main(){
int i,fact=1,number;
clrscr();
printf("Enter a number: ");
scanf("%d",&number);
for(i=1;i<=number;i++){
fact=fact*i;
}
printf("Factorial of %d is: %d",number,fact);
getch();
}
Write a program to print factorial of given number using recursion?
#include<stdio.h>
#include<conio.h>
long factorial(int n) // function to calculate the factorial of a given number.
{
if (n == 0)
return 1;
else
return(n * factorial(n-1)); //calling the function recursively.
}
void main()
{
int number; //declaration of variables.
long fact;
clrscr();
printf("Enter a number: ");
scanf("%d", &number);
fact = factorial(number); //calling a function.
printf("Factorial of %d is %ld\n", number, fact);
getch(); //It reads a character from the keyword.
}
What are actual arguments?
When you create and use functions that need to perform an action on some given values, you need to pass these given values to that function. The values that are being passed into the called function are referred to as actual arguments.
What is a newline escape sequence?
A newline escape sequence is represented by the \n character. This is used to insert a new line when displaying data in the output screen. More spaces can be added by inserting more \n characters. For example, \n\n would insert two spaces. A newline escape sequence can be placed before the actual output expression or after.
What is output redirection?
It is the process of transferring data to an alternative output source other than the display screen. Output redirection allows a program to have its output saved to a file. For example, if you have a program named COMPUTE, typing this on the command line as COMPUTE >DATA can accept input from the user, perform certain computations, then have the output redirected to a file named DATA, instead of showing it on the screen.
What are run-time errors?
These are errors that occur while the program is being executed. One common instance wherein run-time errors can happen is when you are trying to divide a number by zero. When run-time errors occur, program execution will pause, showing which program line caused the error.
What are structure types in C?
Structure types are primarily used to store records. A record is made up of related fields. This makes it easier to organize a group of related data.
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