C Programming Multiple Choice Questions and Answers on Character Class Testing & Conversions for Freshers

1. Which of the following library function is not case-sensitive?

a) toupper()
b) tolower()
c) isdigit()
d) all of the mentioned

Answer: c

2. The following expression can be substituted for.
    if (isalpha(c) && isdigit(c))

a) if (isalnum(c))
b) if (isalphanum(c))
c) if (isalphanumeric(c))
d) none of the mentioned

Answer: d

3. Which of the following will return a non-zero value when checked with isspace(c)?

a) blank
b) newline
c) return
d) all of the mentioned

Answer: d

4. What is the output of this C code?

1.     #include 

2.     #include 

3.     int main()

4.     {

5.         char i = 9;

6.         if (isdigit(i))

7.             printf("digit\n");

8.         else

9.             printf("not digit\n");

10.             return 0;

11.     }

a) digit
b) not digit
c) Depends on the compiler
d) None of the mentioned

Answer: b
.

5. What is the output of this C code?

1.     #include 

2.     #include 

3.     int main()

4.     {

5.         int i = 9;

6.         if (isdigit(i))

7.             printf("digit\n");

8.         else

9.             printf("not digit\n");

10.             return 0;

11.     }

a) digit
b) not digit
c) Depends on the compiler
d) None of the mentioned

Answer: b

6. What is the output of this C code?

1.     #include 

2.     int main()

3.     {

4.         char i = '9';

5.         if (isdigit(i))

6.             printf("digit\n");

7.         else

8.             printf("not digit\n");

9.             return 0;

10.     }

a) digit
b) not digit
c) Depends on the compiler
d) None of the mentioned

Answer: a

7. What is the output of this C code?

1.     #include 

2.     #include 

3.     int main()

4.     {

5.         if (isspace('n'))

6.             printf("space\n");

7.         else

8.             printf("not space\n");

9.             return 0;

10.     }

a) Compile time error
b) space
c) not space
d) None of the mentioned

Answer: b

8. What is the output of this C code?

1.     #include 

2.     #include 

3.     int main()

4.     {

5.         int i = 0;

6.         if (isspace(i))

7.             printf("space\n");

8.         else

9.             printf("not space\n");

10.             return 0;

11.     }

a) Compile time error
b) space
c) not space
d) None of the mentioned

Answer: c

9. Which is true about isaplpha(c), where c is an int that can be represented as an unsigned
    char or EOF.isalpha(c) returns?

a) Non-zero if c is alphabetic
b) 0 if c is not alphabetic
c) Both Non-zero if c is alphabetic & 0 if c is not alphabetic
d) None of the mentioned

Answer: c

10. Which is true about isupper(c), where c is an int that can be represented as an unsigned
    char or EOF.isupper(c) returns?

a) Non-zero if c is upper case
b) 0 if c is not upper case
c) Nothing
d) Both Non-zero if c is upper case & 0 if c is not upper case

Answer: d

11. Which is true about isalnum(c), where c is an int that can be represented as an unsigned
    char or EOF.isalnum(c) returns?

a) Non-zero if isalpha(c) or isdigit(c)
b) 0 if not isalpha(c) or not isdigit(c)
c) Both Non-zero if isalpha(c) or isdigit(c) & 0 if not isalpha(c) or not isdigit(c)
d) None of the mentioned

Answer: c

12. What is the output of this C code?

1.     #include 

2.     #include 

3.     int main()

4.     {

5.         char c = 't';

6.         printf("%d\n", isspace(c));

7.     }

a) Non-zero number
b) Nothing
c) Error
d) t

Answer: a

13. What is the output of this C code?

1.     #include 

2.     #include 

3.     int main()

4.     {

5.         char c = 't';

6.         printf("is :%c\n", tolower('A'));

7.     }

a) A
b) a
c) Non-zero number
d) Zero

Answer: b

14. Which types of input are accepted in toupper(c)?

a) char
b) char *
c) float
d) Both char and char *

Answer: a

15. What is the difference in the ASCII value of capital and non-capital of the same letter is?

a) 1
b) 16
c) 32
d) Depends with compiler

Answer: c