C Programming Questions and Answers – Line Input & Output

C Programming Questions and Answers – Line Input & Output

1.The syntax of fgets is char *fgets(char *line, int maxline, FILE *fp).which is true for fgets.fgets

a) returns line on success

b) On end of file or error it returns NULL.

c) Nothing

d) Both a & b

2.fputs function writes a string to a file that only ends with a newline.

a) true

b) false

c) Depends on the standard

d) Depends on the compiler

3.What is the output of this C code?

#include <stdio.h>

#include <string.h>

int main()

{

char line[3];

fgets(line, 3, stdin);

printf(“%d\n”, strlen(line));

return 0;

}

a) 3

b) 1

c) Any length since line did not end with null character

d) Depends on the standard

4.What is the output of this C code?

#include <stdio.h>

#include <string.h>

int main()

{

char line[3];

FILE *fp;

fp = fopen(“newfile.txt”, “r”);

while (fgets(line, 3, fp))

fputs(line, stdout);

return 0;

}

a) Compilation error

b) Infinite loop

c) Segmentation fault

d) No.of lines present in file newfile

5.What is the output of this C code if 2 character is typed by the user?

#include <stdio.h>

#include <string.h>

int main()

{

char line[3];

fgets(line, 3, stdin);

printf(“%d\n”, line[2]);

return 0;

}

a) Compilation error

b) Undefined behaviour

c) 0

d) 10(ascii value of newline character)

6.fputs adds newline character

a) true

b) false

c) Depends on the standard

d) Undefined behaviour

7.puts function adds newline character

a) true

b) false

c) Depends on the standard

d) Undefined behaviour

8.gets function checks overflow run

a) true

b) false

c) Depends on the standard

d) Depends on the compiler

9.puts does the following when it writes to stdout

a) Deletes everything

b) Adds ‘t’ to the line written.

c) Deletes the terminating ‘n’

d) Adds ‘n’ to the line written.

10.What is the size of array “line” used in fgets(line, maxline, *fp) function?

a) maxline – 1

b) maxline

c) maxline + 1

d) Size is dynamic

11.The following function

int fputs(char *line, FILE *fp)

returns EOF when:

a) ‘?’ character of array line is encountered

b) ‘n’ character in array line is encountered

c) ‘t’ character in array line is encountered

d) When an error occurs

12.Identify X library function for line input and output?

#include <stdio.h>

int X(char *s, FILE *iop)

{

int c;

while (c = *s++)

putc(c, iop);

return ferror(iop) ? EOF : 0;

}

a) getc

b) putc

c) fgets

d) fputs

13.Which function has a return type as char pointer?

a) getline

b) fputs

c) fgets

d) All of the mentioned

14.Which of the following is the right declaration for fgets inside the library?

a) int *fgets(char *line, int maxline, FILE *fp);

b) char *fgets(char *line, int maxline, FILE *fp);

c) char *fgets(char *line, FILE *fp);

d) int *fgets(char *line, FILE *fp);

15.Which is true about fputs.fputs returns?

a) EOF if an error occurs

b) Non-negative if no error

c) Both a & b

d) None of the mentioned

16.gets and puts operate on

a) stdin and stdout

b) files

c) stderr

d) Nothing

17.gets does the following when it reads from stdin

a) Deletes the ‘t’

b) Puts adds it.

c) Deletes the terminating ‘n’

d) Nothing