C Programming Tutorials

C Programming Tutorials And Articles
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This article assumes that readers are aware of what pointers are and how they are used in 'C'. As a quick overview, A pointer is a special variable which holds the address of a variable of same type. For example : Lets say there is a variable 'int a=10' so,a pointer to variable 'a' can be...
The other day I was working on a code where in I was doing some file related operations. I used the function feof() to test whether the end of file has been reached or not. I got into some trouble over the way I used this function in my code, after debugging a bit I found the problem. The problem...
There are times when you write a small or a big code and when you execute it you get a very small and precise output 'Segmentation fault'. In a small piece of code its still easy to debug the reason for this but as the code size grows it becomes very difficult to debug. Here in this article, I am...
If you work 3-4 hours daily on coding in C/C++ then there ought to be some programs, logics, tricks, tips etc which you come across daily. Some are new to only you while others are interesting enough to be shared. Here in this article, I am going to share one interesting program and how I went...
The other day I was searching a bit on Linux viruses on Internet. Though there are quite a few now but still cannot be compared with the volumes that we have on windows. Another thing that I found was the permission robustness that Linux file system has as compared to windows OS. So, whiling...
Being a Linux system programmer there are numerous situations when one needs to deal with files kept on disk. Like opening a file, reading a file(one character at a time, one line at a time, the whole file at a time), seeking in a file and then finally closing it. One can use various library...
Continuing my previous article Understanding File Handling Functions in C, here in this article let us focus on functions like : fread() // read a chunk of data from file fwrite() // Write a chunk of data to file feof() // Check for end of file indicator ferror() // Check for error...
After writing my previous article Virus Code in Linux - C Code That Changes it's Process Name Run Time, I wondered if a process can change its name then why cannot it change its PID. And what if a process can change both its name and PID after lets say every 1 second? Well it will be a difficult...
In this article we will extend our code to print more comprehensive information about a file/directory in a directory. Please Refer Developing Linux Utility like 'ls' in C Developing Linux Utility - Part II Arranging Output in Alphabetical Order Example $ ls -l total 148 ...
Recently I have been writing a lot on Linux files and functions related to file I/O. So, extending the discussion further in this article lets discuss two more important Linux functions : A) access(const char *pathname, int mode) This function checks whether the calling process can access...
If you are a developer then you would definitely be aware of the concept of temporary files. Temporary files, as the name suggest is temporary in its persistence. Either a process creates a temporary file to hold data for certain time or to pass information to another process. An ideal process...
Two of my friends faced a problem with writing a program which finds the LCM(Lowest Common Multiple)/GCD(Greatest Common Divisor) of two positive integers, so I helped them out by writing two functions for each. I thought many others might be having the same problem. So here are the functions:...
Comma-separated expressions were inherited from C. It's likely that you use such expressions in for- and while-loops rather often. Yet, the language rules in this regard are far from being intuitive. First, let's see what a comma separated expression is. An expression may consist of one or...
When a process terminates abnormally it usually tries to send a signal indicating what went wrong. C programs (and UNIX) can trap these for diagnostics. Also user specified communication can take place in this way. Signals are software generated interrupts that are sent to a process when a...
Refer to the recent articles on Understanding File Handling Functions in C & Understanding Advance File Handling Functions in C C communicates with files using a new datatype called a file pointer. This type is defined within stdio.h, and written as FILE *. A file pointer called output_file is...
Calculating the factorial of a number is a basic excercise while learning to program in C, many of us have done it iteratively, it can also be done recursively. I am posting both iterative and recursive versions below. /* Recursive Version */ unsigned int recursive_factorial(int n) ...
A friend of mine who is learning to program in C, was having diffculty in writing a program to find the sum of all the prime numbers between a specified limit (in her case 3-60). I helped her out with the program, and I thought I'll post it here which might help others. /* ** Program to...
When I was learning to C, our proffessor had given us a problem where we had to enter a number into a sorted array so that the array remains sorted even after the insertion. So, I tried it yesterday, here's the code for it. /* ** To insert an inputed number into a previously sorted...
C program to check whether a year is a leap year or not. /* ** C program to check whether an entered year is a leap year or not ** @author: Pradeep ** @date: 02/12/06 */ #include<stdio.h>
One of my friends, who is learning to program in C, asked me about how to write a program which checks an inputed string is a palindrome or not, without using the header file string.h So here's the solution. #include <stdio.h> void main(void) { char str; int len=0,i=0,j,flag=1;