Unit 3 CS 36

Question 1

What are streams?

Answer 1

Streams are data buffers/collectors. The three different streams are input(keyboard), output(message or outcome after running the program), and error (message regarding wrongly written code or syntax issues). Both error and output are based on screen, and input is by keyboard

Question 2

How can streams be manipulated?

Answer 2

Using the stdin, stdout and stderr functions from the standard library (standard in, out, and error)

Question 3

How do we work with files in C?

Answer 3

We have to change the input and output stream files using stdin and stdout.

Question 4

What are the two different ways to input and output to files?

Answer 4

Sequential and Random-Access

Question 5

What are the two functions to manipulate files?

Answer 5

fgets() and fputs()

Question 6

true or false: each file needs it’s own pointer?

Answer 6

true. to initialize a file pointer, you have to do FILE *cPtr; to point to a file structure

Question 7

What does the fopen function do?

Answer 7

It takes a file name and a mode as it’s arguments (ex: fopen(“file.exe”, “w”); in this case, the mode of the file is write). If this file doesn’t exist, fopen creates a new file with that given name “file.exe”

Question 8

File

Answer 8

collection of data or information that is stored on a computer’s storage. For example, a hard drive or a USB stick

Question 9

What happens if fopen is equal to NULL?

Answer 9

That means there is an error regarding opening the file

Question 10

True or false, you always have to open a file before you manipulate the file?

Answer 10

True, you have to use fopen and then manipulate the file, and when you are finally done manipulating everything, you close using fclose(). Remember, fopen is equal to the address of a file, meaning that you must use a pointer of a file to store this value

Question 11

Let’s say you make a pointer (FILE *cPtr) and then you do cPtr = fopen(“file name”, “mode”), what does the pointer equal to if this assignment does not work?

Answer 11

It is equal to NULL

Question 12

EOF

Answer 12

End of File value that tells you you have reached the end of the file that you are reading

Question 13

feof(stdin)

Answer 13

looks for EOF (end of file) indicator

Question 14

Random-Access Files

Answer 14

This is when a file is opened through the “wb” mode instead of “w” or “r” (write or read, and this represents binary write) and then a structure is used to fill in certain values. The file is represented in binary form

Question 15

instance

Answer 15

The variable of a structure

Question 16

a random access file is useful when you are using a struct to write values into the file

Answer 16

Yes

Question 17

Review how fwrite works when the file is in binary write mode

Answer 17

Yes

Question 18

“wb” vs “rb+”

Answer 18

wb is used create files and write new information, whereas rb+ is useful for updating information among the already created random-access file

Question 18

True or False, is the correct format for scanf like this: scanf(“%d”, &value1);

Answer 18

Yes, you must include a percentage sign before the type of data, as well as an ampersand next to the value in scanf

Question 19

ListedNode

Answer 19

This is a linked list that is created when you have a structure with a self-referential pointer, and a char variable within the structure.