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  • No special processing of the data occurs and each byte of data is transferred to or from the disk unprocessed.
  • C Programming Language places no constructs on the file, and it may be read from, or written to, in any manner chosen by the programmer.

Binary files can be either processed sequentially or, depending on the needs of the application, they can be processed using random access techniques. In C Programming Language, processing a file using random access techniques involves moving the current file position to an appropriate place in the file before reading or writing data. This indicates a second characteristic of binary files – they a generally processed using read and write operations simultaneously.

For example, a database file will be created and processed as a binary file. A record update operation will involve locating the appropriate record, reading the record into memory, modifying it in some way, and finally writing the record back to disk at its appropriate location in the file. These kinds of operations are common to many binary files, but are rarely found in applications that process text files.

For all file operations you should always follow the 5-step plan as outlined below.

  1. Declare file pointer.
  2. Attach the file pointer to the file (open file).
  3. Check file opened correctly.
  4. Read or Write the data from or to the file.
  5. Close the file.

Operations on files


In C, we usually create variables of type FILE * to point to a file located on the computer.

FILE *file_pointer_name;


FILE * f1, * f2;

Open files

First things first: we have to open a file to be able to do anything else with it. For this, we use fopen function, like all the I/O functions, is made available by the stdio.h library. The fopen() function prototype is as follows.

FILE *fopen(char *filename, char *mode);

In the above prototype, there are two arguments:

  • filename is a string containing the name of the file to be opened. So if your file sits in the same directory as your C source file, you can simply enter the filename in here - this is probably the one you'll use most.
  • mode determines how the file may be accessed.
Mode Meaning
“r” Open a file for read only, starts at beginning of file (default mode).
“w” Write-only, truncates existing file to zero length or create a new file for writing.
“a” Write-only, starts at end of file if file exists,otherwise creates a new file for writing.
“r+” Open a file for read-write, starts at beginning of file. If the file is not exist, it will cause an error.
“w+” Read-write, truncates existing file to zero length or creates a new file for reading and writing.
“a+” Read-write, starts at end of file if file exists, otherwise creates a new file for reading and writing.

So there are 12 different values that could be used: "rt", "wt", "at", "r+t", "w+t", "a+t" and "rb", "wb", "ab", "r+b", "w+b", "a+b".

Character Type
“t” Text File
“b” Binary File
When work with the text file, you also can use only "r", "w", "a", "r", "w”, "a", instead of "rt", "wt", "at", "r+t", "w+t", "a+t" respectively.

Questions & Answers

show that the set of all natural number form semi group under the composition of addition
Nikhil Reply
explain and give four Example hyperbolic function
Lukman Reply
⅗ ⅔½
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the fraction, the value of the fraction becomes 2/3. Find the original fraction. 2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
1. x + 6 2 -------------- = _ x + 9 + 6 3 x + 6 3 ----------- x -- (cross multiply) x + 15 2 3(x + 6) = 2(x + 15) 3x + 18 = 2x + 30 (-2x from both) x + 18 = 30 (-18 from both) x = 12 Test: 12 + 6 18 2 -------------- = --- = --- 12 + 9 + 6 27 3
2. (x) + (x + 2) = 60 2x + 2 = 60 2x = 58 x = 29 29, 30, & 31
on number 2 question How did you got 2x +2
combine like terms. x + x + 2 is same as 2x + 2
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
mariel Reply
Mark = x,. Don = 3x + 1 x + 3x + 1 = 113 4x = 112, x = 28 Mark = 28, Don = 85, 28 + 85 = 113
how do I set up the problem?
Harshika Reply
what is a solution set?
find the subring of gaussian integers?
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Shirley Reply
please can go further on polynomials quadratic
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I need quadratic equation link to Alpa Beta
Abdullahi Reply
find the value of 2x=32
Felix Reply
divide by 2 on each side of the equal sign to solve for x
Want to review on complex number 1.What are complex number 2.How to solve complex number problems.
yes i wantt to review
use the y -intercept and slope to sketch the graph of the equation y=6x
Only Reply
how do we prove the quadratic formular
Seidu Reply
please help me prove quadratic formula
hello, if you have a question about Algebra 2. I may be able to help. I am an Algebra 2 Teacher
Shirley Reply
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what is math number
Tric Reply
x-2y+3z=-3 2x-y+z=7 -x+3y-z=6
Sidiki Reply
can you teacch how to solve that🙏
Solve for the first variable in one of the equations, then substitute the result into the other equation. Point For: (6111,4111,−411)(6111,4111,-411) Equation Form: x=6111,y=4111,z=−411x=6111,y=4111,z=-411
x=61/11 y=41/11 z=−4/11 x=61/11 y=41/11 z=-4/11
Need help solving this problem (2/7)^-2
Simone Reply
what is the coefficient of -4×
Mehri Reply
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Kimberly Reply
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
August Reply
What is the expressiin for seven less than four times the number of nickels
Leonardo Reply
How do i figure this problem out.
how do you translate this in Algebraic Expressions
linda Reply
why surface tension is zero at critical temperature
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
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Source:  OpenStax, Introduction to computer science. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10776/1.1
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