Skip to main content

Arrays of C Program

Arrays in C programming starts with memory addresses. Yes the compiler handles arrays as memory addresses.
  • Similar elements group together with a single name is called array
  • the indexing always starts with 0 and ends at n-1 (if the size of the array is n)
  • Array elements stores in consecutive memory location.
The array elements usually stores in consecutive memory location. For example,
int a[10];  //Array with size 10
the above example is an integer array with size 10 or this array can hold 10 variables.
The elements starts from a[0], a[1], a[2]…..a[9], so totally there are 10 elements.
Array elements values memory address location
a[0] 32 600AH  (This address is called as the base address)
a[1] 34 600EH
a[2] 23 6012H
a[3] 35 6016H
a[4] 45 601AH
a[5] 67 601EH
a[6] 56 6022H
a[7] 1 6026H
a[8] 34 602AH
a[9] 25 602EH
The memory addresses shown above are in hexadecimal, that’s why each address suffixed with a letter H. The memory addresses in each machine will be different.
The base address is the address where the first element of the array is stored. Usually it is represented as &a[0] or simply a.
The entire array is represented as an address by specifying the base address alone to various other elements of C programming like passing array to functions involves sending the base address only.
For the above table, here is the declaration syntax
int a[10]={32,34,23,35,45,67,56,1,34,25};
int a[]={32,34,23,35,45,67,56,1,34,25};
A simple program to get some numbers and print them on the screen
int main()
int a[10], j; //declaration of array “a” and its index j
printf(“Enter all the 10 numbers”);
for(j=0;j<10;j++) //get the numbers using a for loop which executes for 10 times (0 to 9)
scanf(“%d”, &a[j]);
for(j=0;j<10;j++) //print the numbers using a for loop which executes for 10 times (0 to 9)
return 0;
In the above example, j varies from 0 to 9 which means the loop will execute 10 times for the array a like this
a[j] when j=0 then a[0]
a[j] when j=1 then a[1]
a[j] when j=2 then a[2]…. and so on
like this the input is entered through the keyboard and same for printing the output.

 T S Pradeep Kumar


Popular posts from this blog

AWK Scripts for NS2 to process data from Trace Files

AWK Scripts are very good in processing the data from the log (trace files) which we get from NS2. If you want to process the trace file manually, here is the detailHere is a sample of trace file from NS2 (However ns2 supports a new type of trace file also), but this post will make you understand the old trace format only.r 0.030085562 _0_ MAC  --- 0 message 32 [0 ffffffff 1 800] ------- [1:255 -1:255 32 0] r 0.030110562 _0_ RTR  --- 0 message 32 [0 ffffffff 1 800] ------- [1:255 -1:255 32 0] s 1.119926192 _0_ RTR  --- 1 message 32 [0 0 0 0] ------- [0:255 -1:255 32 0]
AWK Scripts are very good in processing the data column wise. For example
the first column in the above trace file represents r, s which indicates receive, sent respectively. If we want to trace the entire r and s alone from this trace file we can represent it as $1
$1 represents ACTION
$2 Time
$3 Node ID
$4 Layer
$5 Flags
$6 seqno
$7 type
$8 Size
$14 Energy (if the network nodes includes EnergyModel)To run the awk script in Li…

nam installation - Segmentation Fault (Solved)

If you are encountering "Segmentation Fault" error while running nam in Ubuntu 14.04 or Linux Mint 17+ editions, this post will be helpful for you.

Download the nam file from this link

First, remove the nam which was installed earlier using the following command 

pradeep@localhost $] sudo apt-get remove nam

and install the new nam which was downloaded just now. go to the folder where the file was downloaded and issue the following command

pradeep@localhost $]  sudo dpkg --install nam_1.15-10_i386.deb

See the screenshot below to install and use nam

 T S Pradeep Kumar

Installation of ns2 in Ubuntu 18.04 - NS2 Tutorial # 2

ns2 installation in Ubuntu 18.04

Unlike earlier version of ubuntu, the 18,04 version does not support the direct installation of ns2, because of the latest C/C++ compiler (7.x), but the latest C/C++ compiler supported by ns2 is gcc-4.8. So this post and video tells you about the installation of gcc-4.8 version, then ns2 and then configuration.
Here are the steps, Please follow the video given below for more information.

$] tar zxvf ns-allinone-2.35.tar.gz

$] sudo apt install gcc-4.8 g++-4.8

if you have installed ubuntu just now, you can try these commands also in the beginning

$] sudo apt update
$] sudo apt install build-essential autoconf automake libxmu-dev

$] cd ns-allinone-2.35/ns-2.35
$] gedit
$] gedit linkstate/ls.h

line number 137, change erase to this->erase
$] cd ..
$] ./install

export PATH=$PATH:/home/pradeepkumar/ns-allinone-2.35/bin:/home/pradeepkumar/ns-allinone-2.35/tcl8.5.10/unix:/home/pradeepkumar/ns-allinone-2.35/tk8.5.10/unix