CBSE Class 12 Computer Science Strings Assignment

Fill ups and Multiple Choice Questions:

Question. What is the length of null string?
Answer: 0 (zero)

Question. Every string must be terminated by __?
Answer: Null Character

Question. Which of the following function is used to reverse the string?
Answer: strrev

Question. Which of the following input function cannot be used to input multiword string?
Answer: scanf()

Question. The function strcmp (“Abcd” ,”ABCD”) will return?
Answer: Negative value

Question. Which of the following function is correct in case of conversion of string digits into their integer value?
a) x =atoi(string)
b) x = stoi(string)
c) x = chartoint(string)
d) all of these

Answer: x =atoi(string)

Question. A string can be stored as an array of ______________
Answer: char

Question. The function strlen(“India is great”) will return the length of string ___________
Answer: 14

Question. __________ function is used to read a complete string.
Answer: gets

Question. _____________ function is used to read a character at a time.
Answer: getchar

Question. How will you declare a string named student with length 50?
Answer: char student[50];

Question. If we consider the string declaration as “char x[10];”, what is the length of the string that can be correctly represented by x?
Answer: 10

Question. If the function strcat(s1,s2) is implemented , then the concatenation will return?
Answer: s2 at the end of s1

Question. Which of the following operation could not be performed on character string with string functions?
a) Combining a string
b) copying a string to another
c) Comparing strings for equality
d) Removing a string

Answer: Removing a string

Question. C does not support the string data type however strings are handled as an array of?
Answer: char

Question. What is missing in this string initialization: char name[8] = {‘r’, ‘a’, ‘e’,‘t’ }?
Answer: \0

Question. To declare and initialized a empty string, a 10 element character array named x, we have char x[10] = “ “ ; What will be the other way for the same?
Answer: char x[10]={‘\0’};

State Whether True or False

Question. A string is represented as array of characters?
Answer: true

Question. strcpy() function is used to copy strings?
Answer: true

Question. To reverse a string, we need two string handling functions strcpy() & strcmp()?
Answer: false

Question. To use string library functions, we have to include header file string.h in our program?
Answer: true

Strings Class 12 Computer Exercise Questions

Question. What is special about the array of char?
Answer: char arrays have special importance in C Language. There is no data type in C to store strings. Therefore, to store string data in, char arrays are being used in C language. To store strings in C, we have to declare char arrays.
For example:
char city[20];
In this example, char array named city has been declared which can store city name with maximum of 20 characters.

Question. What is string?
Answer: String is a combination of one or more characters. It is always enclosed in double quotes. They are terminated by null character (\0) in c. To store strings in c, we use char array. For example: char city[20];
It declares a string variable named city. It can store the string of maximum 20 characters.
Consider another example: char city[20]=”Sunam\0”;
It initializes a string variable named city of length 20 and stores “Sunam” as string value. This value is terminated with null character ‘\0’.

Question. What is the purpose of the null character?
Answer: Null character is also called empty character. It can be represented with the symbol ‘\0’. The length of null character is C is zero. Null character is used to terminate the string in C language. For example: char city[10]= “Sunam\0”;
It declares a string variable named city of length 10 and stores “Sunam” as string value. This value is terminated with null character ‘\0’.

Question. Give the declaration for a string called student, which holds up to 50 characters. Show two ways to initialize the string in the declaration?
Answer: String declaration for student with 50 characters is:
char student[50];
Two methods for declaring strings are:
char student[50]=“Ram\0”;
char student[50]={‘R’, ‘a’, ‘m’,’\0’};

Question. What is the limit of char array?
Answer: Char arrays have a special importance in C language. There is not primitive data type to store string data in c. therefore, to store string values in c, we have to use char arrays. Limit (length) of char array defines the length of string. In c clanguage, maximum length of a string in char array can be 65535. Therefore, we can not extend the limit of char array more than 65535.

Question. What is a difference between “A” and ‘A’?
Answer: “A” is a string while ‘A’ is a character. “A” is string because any string value must be enclosed in double quotes and ‘A’ is char because any char value must be enclosed in single quotes in c language.

Question. Give the difference between putchar() and puts()?
Answer: The difference between putchar() and puts() functions is as follows: puchar() function: This is the unformatted character output function. This function is used to output a single unformatted character on the monitor screen.  puts() function: This is the unformatted string output function. This function is used to output an unformatted string on the monitor screen.

Question. List the various functions that can be used to perform the I/O of the string data?
Answer: A string can be read-in or written-out using the input/output functions. Some of the commonly used string input/output functions are explained below:
Reading Strings (String Input Functions):
• scanf() : This function is used to input single word formatted string
• gets() : This function is used to input multiword unformatted string
• getchar() : This function is used to input unformatted single character
Writing Strings (String Output Functions):
• printf() : This function is used to output formatted string
• puts(): This function is used to output unformatted string
• putchar(): This function is used to output unformatted single character

Question. Can we use scanf() to read a string? If no, then give reason. Why it is wrong to use the & symbol when reading in a string with scanf()?
Answer: Yes, we cam use scanf() to read a string. But this function can not be used to inpute multiword strings in C language. There is not data type for storing string data in C. For this, we use char arrays. Name of an array in C represents the address of the first element of array. So, when we use char array in scanf() function, array name itself represents the address of string variable. So, it will be wrong to use the & symbol when reading a string with scanf() function.

Question. What is stored in the str, if each of the following values, separately, is read in using a single call to scanf()? char str[10];
a) cityscape
b) New Delhi
c) one or more blanks
Answer: a) cityscape
b) New
c) one

Question. Explain strlen() function with suitable example.
Answer: Function strlen() stands for string length. This function is used to count the total number of characters in the given string. This function is present in the string.h header file. Therefore, to use this function, we have to include the string.h header file in our program. Following code shows how to use this function:
strlen(“punjab”);
This function returns 6 as string length because the string “Punjab” contains 6 characters.

Question. Explain strrev() function with suitable example.
Answer: Function strrev stands for string reverse. This function is used to reverse the given string value. This function is present in the string.h header file. Therefore, to use this function, we have to include the string.h header file in our program. Following code shows how to use this function:
strrev(“Punjab”);
It reverses the given string to bajnuP.

Question. Explain strcpy() function with suitable example.
Answer: Function strcpy stands for string copy. This function is used to copy a string value into string variable. This function is present in the string.h header file. Therefore, to use this function, we have to include the string.h header file in our program. Following code shows how to use this function.
strcpy(str, “Punjab”);
It copy/store the string value “Punjab” into the string variable str.

Question. Explain strcat() function with suitable example.
Answer: Function strrev stands for string concatenation. This function is used to combines the two strings. It appends 2nd string value at the end of first string value. This function is present in the string.h header file. Therefore, to use this function, we have to include the string.h header file in our program. Following code shows how to use this function. Let the two strings are: char str1[10]=“Sunam”; char str2[10]=“City”;
strcat(str2, str1);
It adds value of str1 at the end of str2 and make it – CitySunam

Question. Explain strcmp() function with suitable example.
Answer: Function strcmp stands for string compares. The strcmp( ) function is used to compare two strings. It returns one of the three possible values: zero, negative, or positive. It uses ASCII value of characters to compare strings. The function strcmp() is present in the string.h header file. Therefore, to use this function, we have to include the string.h header file in our program. Consider the the following example:
If ASCII values of 1st string is equal to ASCII values of 2nd string, It returns 0 e.g. strcmp(“punjab”,“punjab”) returns 0
If ASCII values of 1st string is less than the ASCII values of 2nd string, It returns negative value e.g. strcmp(“india”,“punjab”) return –ve value
If ASCII values of 1st string is greater than ASCII values of 2nd string, It returns +ve value e.g. strcmp(“punjab”,”india”) return +ve value

Question. Explain strupr() function with suitable example.
Answer: Function strupr stands for string upper. This function is used to convert the given string into Upper case (i.e. in capital letter). This function is present in the string.h header file. Therefore, to use this function, we have to include the string.h header file in our program. Following code shows how to use this function: strupr(“Punjab”); It converts the given string into PUNJAB.

Question. Explain strlwr() function with suitable example.
Answer: Function strlwr stands for string lower. This function is used to convert the given string into lower case (i.e. in small letter). This function is present in the string.h header file. Therefore, to use this function, we have to include the string.h header file in our program. Following code shows how to use this function: strlwr(“PUNJAB”); It converts the given string into punjab.

Question. Explain atoi () function with suitable example.
Answer: Function atoi stands for ascii to integer. This function converts the string number into integer value. This function is present in the stdlib.h header file. Therefore, to use this function, we have to include the stdlib.h header file in our program. Consider the following example: atoi(“456”); It will convert the string number “456” into integer value 456.