Appian Corporation Most Frequently Asked C Language Interview Questions Answers
What are the different data types in C?
The basic data types are int, char, and float. Int is used to declare variables that will be storing integer values. Float is used to store real numbers. Char can store individual character values.
What is the general form of a C program?
A C program begins with the preprocessor directives, in which the programmer would specify which header file and what constants (if any) to be used. This is followed by the main function heading. Within the main function lies the variable declaration and program statement.
What is the difference between functions abs() and fabs()?
These 2 functions basically perform the same action, which is to get the absolute value of the given value. Abs() is used for integer values, while fabs() is used for floating type numbers. Also, the prototype for abs() is under <stdlib.h>, while fabs() is under <math.h>.
What are formal parameters?
In using functions in a C program, formal parameters contain the values that were passed by the calling function. The values are substituted in these formal parameters and used in whatever operations as indicated within the main body of the called function.
What are control structures?
Control structures take charge at which instructions are to be performed in a program. This means that program flow may not necessarily move from one statement to the next one, but rather some alternative portions may need to be pass into or bypassed from, depending on the outcome of the conditional statements.
Write a simple code fragment that will check if a number is positive or negative.
If (num>=0)
printf("number is positive");
else
printf ("number is negative");
When is a “switch” statement preferable over an “if” statement?
The switch statement is best used when dealing with selections based on a single variable or expression. However, switch statements can only evaluate integer and character data types.
What are global variables and how do you declare them?
Global variables are variables that can be accessed and manipulated anywhere in the program. To make a variable global, place the variable declaration on the upper portion of the program, just after the preprocessor directives section.
What are enumerated types?
Enumerated types allow the programmer to use more meaningful words as values to a variable. Each item in the enumerated type variable is actually associated with a numeric code. For example, one can create an enumerated type variable named DAYS whose values are Monday, Tuesday… Sunday.
What does the function toupper() do?
It is used to convert any letter to its upper case mode. Toupper() function prototype is declared in <ctype.h>. Note that this function will only convert a single character, and not an entire string.
Is it possible to have a function as a parameter in another function?
Yes, that is allowed in C programming. You just need to include the entire function prototype into the parameter field of the other function where it is to be used.
What are multidimensional arrays?
Multidimensional arrays are capable of storing data in a two or more dimensional structure. For example, you can use a 2 dimensional array to store the current position of pieces in a chess game, or position of players in a tic-tac-toe program.
Which function in C can be used to append a string to another string?
The strcat function. It takes two parameters, the source string and the string value to be appended to the source string.
What is the difference between functions getch() and getche()?
Both functions will accept a character input value from the user. When using getch(), the key that was pressed will not appear on the screen, and is automatically captured and assigned to a variable. When using getche(), the key that was pressed by the user will appear on the screen, while at the same time being assigned to a variable.
Dothese two program statements perform the same output? 1) scanf(“%c”, &letter); 2) letter=getchar()
Yes, they both do the exact same thing, which is to accept the next key pressed by the user and assign it to variable named letter.
What is the advantage of a random access file?
If the amount of data stored in a file is fairly large, the use of random access will allow you to search through it quicker. If it had been a sequential access file, you would have to go through one record at a time until you reach the target data. A random access file lets you jump directly to the target address where data is located.
In a switch statement, what will happen if a break statement is omitted?
If a break statement was not placed at the end of a particular case portion? It will move on to the next case portion, possibly causing incorrect output.
Describe how arrays can be passed to a user defined function
One thing to note is that you cannot pass the entire array to a function. Instead, you pass to it a pointer that will point to the array first element in memory. To do this, you indicate the name of the array without the brackets.
What are pointers?
Pointers point to specific areas in the memory. Pointers contain the address of a variable, which in turn may contain a value or even an address to another memory.
Can you pass an entire structure to functions?
Yes, it is possible to pass an entire structure to a function in a call by method style. However, some programmers prefer declaring the structure globally, then pass a variable of that structure type to a function. This method helps maintain consistency and uniformity in terms of argument type.
What is gets() function?
The gets() function allows a full line data entry from the user. When the user presses the enter key to end the input, the entire line of characters is stored to a string variable. Note that the enter key is not included in the variable, but instead a null terminator \0 is placed after the last character.
The % symbol has a special use in a printf statement. How would you place this character as part of the output on the screen?
You can do this by using %% in the printf statement. For example, you can write printf(“10%%”) to have the output appear as 10% on the screen.
What are the different data types in C?
The basic data types are int, char, and float. Int is used to declare variables that will be storing integer values. Float is used to store real numbers. Char can store individual character values.
What is the general form of a C program?
A C program begins with the preprocessor directives, in which the programmer would specify which header file and what constants (if any) to be used. This is followed by the main function heading. Within the main function lies the variable declaration and program statement.
What is the difference between functions abs() and fabs()?
These 2 functions basically perform the same action, which is to get the absolute value of the given value. Abs() is used for integer values, while fabs() is used for floating type numbers. Also, the prototype for abs() is under <stdlib.h>, while fabs() is under <math.h>.
What are formal parameters?
In using functions in a C program, formal parameters contain the values that were passed by the calling function. The values are substituted in these formal parameters and used in whatever operations as indicated within the main body of the called function.
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| Appian Corporation Most Frequently Asked C Language Interview Questions Answers |
What are control structures?
Control structures take charge at which instructions are to be performed in a program. This means that program flow may not necessarily move from one statement to the next one, but rather some alternative portions may need to be pass into or bypassed from, depending on the outcome of the conditional statements.
Write a simple code fragment that will check if a number is positive or negative.
If (num>=0)
printf("number is positive");
else
printf ("number is negative");
When is a “switch” statement preferable over an “if” statement?
The switch statement is best used when dealing with selections based on a single variable or expression. However, switch statements can only evaluate integer and character data types.
What are global variables and how do you declare them?
Global variables are variables that can be accessed and manipulated anywhere in the program. To make a variable global, place the variable declaration on the upper portion of the program, just after the preprocessor directives section.
What are enumerated types?
Enumerated types allow the programmer to use more meaningful words as values to a variable. Each item in the enumerated type variable is actually associated with a numeric code. For example, one can create an enumerated type variable named DAYS whose values are Monday, Tuesday… Sunday.
What does the function toupper() do?
It is used to convert any letter to its upper case mode. Toupper() function prototype is declared in <ctype.h>. Note that this function will only convert a single character, and not an entire string.
Is it possible to have a function as a parameter in another function?
Yes, that is allowed in C programming. You just need to include the entire function prototype into the parameter field of the other function where it is to be used.
What are multidimensional arrays?
Multidimensional arrays are capable of storing data in a two or more dimensional structure. For example, you can use a 2 dimensional array to store the current position of pieces in a chess game, or position of players in a tic-tac-toe program.
Which function in C can be used to append a string to another string?
The strcat function. It takes two parameters, the source string and the string value to be appended to the source string.
What is the difference between functions getch() and getche()?
Both functions will accept a character input value from the user. When using getch(), the key that was pressed will not appear on the screen, and is automatically captured and assigned to a variable. When using getche(), the key that was pressed by the user will appear on the screen, while at the same time being assigned to a variable.
Dothese two program statements perform the same output? 1) scanf(“%c”, &letter); 2) letter=getchar()
Yes, they both do the exact same thing, which is to accept the next key pressed by the user and assign it to variable named letter.
What is the advantage of a random access file?
If the amount of data stored in a file is fairly large, the use of random access will allow you to search through it quicker. If it had been a sequential access file, you would have to go through one record at a time until you reach the target data. A random access file lets you jump directly to the target address where data is located.
In a switch statement, what will happen if a break statement is omitted?
If a break statement was not placed at the end of a particular case portion? It will move on to the next case portion, possibly causing incorrect output.
Describe how arrays can be passed to a user defined function
One thing to note is that you cannot pass the entire array to a function. Instead, you pass to it a pointer that will point to the array first element in memory. To do this, you indicate the name of the array without the brackets.
What are pointers?
Pointers point to specific areas in the memory. Pointers contain the address of a variable, which in turn may contain a value or even an address to another memory.
Can you pass an entire structure to functions?
Yes, it is possible to pass an entire structure to a function in a call by method style. However, some programmers prefer declaring the structure globally, then pass a variable of that structure type to a function. This method helps maintain consistency and uniformity in terms of argument type.
What is gets() function?
The gets() function allows a full line data entry from the user. When the user presses the enter key to end the input, the entire line of characters is stored to a string variable. Note that the enter key is not included in the variable, but instead a null terminator \0 is placed after the last character.
The % symbol has a special use in a printf statement. How would you place this character as part of the output on the screen?
You can do this by using %% in the printf statement. For example, you can write printf(“10%%”) to have the output appear as 10% on the screen.
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