ExamAdept

To print out a and b given below, which of the following printf() statement will you use?

#include<stdio.h>

float a=3.14;
double b=3.14;

A:

printf("%f %lf", a, b);

B:

printf("%Lf %f", a, b);

C:

printf("%Lf %Lf", a, b);

D:

printf("%f %Lf", a, b);

Answer: A

To print a float value, %f is used as format specifier.

To print a double value, %lf is used as format specifier.

Therefore, the answer is printf("%f %lf", a, b);

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Which of the following operations can be performed on the file "NOTES.TXT" using the below code?

FILE *fp;
fp = fopen("NOTES.TXT", "r+");

A:

Reading

B:

Writing

C:

Appending

D:

Read and Write

Answer: D

r+ Open an existing file for update (reading and writing).

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What does fp point to in the program ?

#include<stdio.h>

int main()
{
    FILE *fp;
    fp=fopen("trial", "r");
    return 0;
}

A:

The first character in the file

B:

A structure which contains a char pointer which points to the first character of a file.

C:

The name of the file.

D:

The last character in the file.

Answer: B

The fp is a structure which contains a char pointer which points to the first character of a file.

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What is the purpose of "rb" in fopen() function used below in the code?

FILE *fp;
fp = fopen("source.txt", "rb");

A:

open "source.txt" in binary mode for reading

B:

open "source.txt" in binary mode for reading and writing

C:

Create a new file "source.txt" for reading and writing

D:

None of above

Answer: A

The file source.txt will be opened in the binary mode.

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In a file contains the line "I am a boy\r\n" then on reading this line into the array str using fgets(). What will str contain?

A:

"I am a boy\r\n\0"

B:

"I am a boy\r\0"

C:

"I am a boy\n\0"

D:

"I am a boy"

Answer: C

Declaration: char *fgets(char *s, int n, FILE *stream);

fgets reads characters from stream into the string s. It stops when it reads either n - 1 characters or a newline character, whichever comes first.

Therefore, the string str contain "I am a boy\n\0"

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Questions for: Input Output