Questions and answers for exam Preparation

MCQs

Total Questions : 35 | Page 2 of 4 pages

Which of the following statement is correct about the program?

#include<stdio.h>
int main()
{
FILE *fp;
char str[11], ch;
int i=0;
fp = fopen("INPUT.TXT", "r");
while((ch=getc(fp))!=EOF)
{
if(ch == '\n' || ch == ' ')
{
str[i]='\0';
strrev(str);
printf("%s", str);
i=0;
}
else
str[i++]=ch;
}
fclose(fp);
return 0;
}

The code writes a text to a file
The code reads a text files and display its content in reverse order
The code writes a text to a file in reverse order
None of above

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Answer: Option B. -> The code reads a text files and display its content in reverse order

This program reads the file INPUT.TXT and store it in the string str after reversing

the string using strrev function.

Question 12.

Which of the following statement is correct about the program?

#include<stdio.h>
int main()
{
FILE *fp;
char ch;
int i=1;
fp = fopen("myfile.c", "r");
while((ch=getc(fp))!=EOF)
{
if(ch == '\n')
i++;
}
fclose(fp);
return 0;
}

The code counts number of characters in the file
The code counts number of words in the file
The code counts number of blank lines in the file
The code counts number of lines in the file

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Answer: Option D. -> The code counts number of lines in the file

This program counts the number of lines in the file myfile.c by counting the character '`setminus`n' in that file.

Question 13.

Point out the error in the program?

#include<stdio.h>
/* Assume there is a file called 'file.c' in c:\tc directory. */
int main()
{
FILE *fp;
fp=fopen("c:\tc\file.c", "r");
if(!fp)
printf("Unable to open file.");
fclose(fp);
return 0;
}

No error, No output.
Program crashes at run time.
Output: Unable to open file.
None of above

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Answer: Option C. -> Output: Unable to open file.

The path of file name must be given as "c: `setminus` `setminus` tc `setminus`file.c"

Question 14.

Point out the error in the program?

#include<stdio.h>
int main()
{
FILE *fp;
fp=fopen("trial", "r");
fseek(fp, "20", SEEK_SET);
fclose(fp);
return 0;
}

Error: unrecognised Keyword SEEK_SET
Error: fseek() long offset value
No error
None of above

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Answer: Option B. -> Error: fseek() long offset value

Instead of "20" use 20L since fseek() need a long offset value.

Question 15.

Point out the error in the program?

#include<stdio.h>
int main()
{
char ch;
int i;
scanf("%c", &i);
scanf("%d", &ch);
printf("%c %d", ch, i);
return 0;
}

Error: suspicious char to in conversion in scanf()
Error: we may not get input for second scanf() statement
No error
None of above

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Answer: Option B. -> Error: we may not get input for second scanf() statement

Question 16.

Point out the error in the program?

#include<stdio.h>
#include<stdlib.h>
int main()
{
unsigned char;
FILE *fp;
fp=fopen("trial", "r");
if(!fp)
{
printf("Unable to open file");
exit(1);
}
fclose(fp);
return 0;
}

Error: in unsigned char statement
Error: unknown file pointer
No error
None of above

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Answer: Option C. -> No error

This program tries to open the file trial.txt in read mode. If file not exists or unable to

read it prints "Unable to open file" and then terminate the program.

If file exists, it simply close the file and then terminates the program.

Question 17.

What will be the output of the program if value 25 given to scanf()?

#include<stdio.h>
int main()
{
int i;
printf("%d\n", scanf("%d", &i));
return 0;
}

Discuss Question

Answer: Option C. -> 1

The scanf function returns the number of input is given.

printf("%d`setminus`n", scanf("%d", &i)); The scanf function returns the value 1(one).

Therefore, the output of the program is '1'.

Question 18.

What will be the output of the program ?

#include<stdio.h>
int main()
{
FILE *fp;
char ch, str[7];
fp=fopen("try.c", "r"); /* file 'try.c' contains "This is Nagpur" */
fseek(fp, 9L, SEEK_CUR);
fgets(str, 5, fp);
puts(str);
return 0;
}