Compiling and running program by amending messages

Now we will change the message written in file message.m. Either you may edit this file, with your favorite editor (like nano, pico, joe, emacs, vim, slap or some thing difference).

Also read this for additional information.

or we can copy file form the message Bank. We will follow the later approach. Below, we are copy file 102Address.m from Bank folder:

|> cp ../src/application/Bank/102Address.m ../src/application/message.m
|> make
|> ./main
Principal
Panth Rattan Shiri Gurcharan Singh Tohra Complex
Guru Nanak Dev Engineering College
Gill Park
Ludhiana - 141006
India

Study message.m, which is, at present, a copy of 102Address.m file and the output of the program. You will find that we have used puts() function for each line. It will be nice, if we can use only one puts(). Try following:

|> cp ../src/application/Bank/103AddressOnePuts.m ../src/application/message.m
|> make
|> ./main

Now, in file message.m, there is only one puts() function. But you will find strange character in the message, which is \n. \n is equivalent of Enter or Return key of the keyboard. It will insert new line.

In the above message.m we used one puts() and all the message typed without the use of Enter key. This makes to read it difficult. It goes outside the screen with. This problem can be resolved by typing \ before hitting Enter at the desired location. Normally, we don’t wish to type text beyond 72th column. So type \ and press Enter somewhere near column number from 765 to 72. Study following case:

|> cp ../src/application/Bank/104AddressOnePutsContentMultiLine.m ../src/application/message.m
|> make
|> ./main

Now, study file ../src/application/Bank/105AddressOnePutsContentMultiLineBetter.m

This file is named as “Better”. Why? Do you agree or not? Discuss in “General Forum” at Guru@GNE

Sometimes we need to do things a number of times. Like to improve our writing, we may be asked to write a particular line 10 times. If we do something wrong, teacher may direct us to write something, 10 times, as a part of punishment. In that case, what you will do? Will you write puts() 10 times, or copy paste, line to be repeated, 10 time. Ok, you may afford to copy for 10 times, what you will do, if you are asked to repeat it for 100 times.

For such tasks, computer languages offer, looping facility. One of such facility, in C, is call for. Study next file:

|> cp ../src/application/Bank/106Punishment.m ../src/application/message.m
|> make
|> ./main

What you found new in this file?

for ( int i = 1; i <= 10; i++ )

The above line make next line:

puts(" I will switch off lights, fans and AC when leaving room");

to execute 10 times. Great!

It instruct computer to execute puts() till value of i is less than 10 or is equal to 10. i will have starting value of 1, i.e. initial value if i is 1, and will be incremented by 1 each time puts() is executed. int in above line, does not stand for initial, but ot stands for Integer. As we need to count lines we wrote, and count number can’t be real / fractional number, and it has to be Integer, so we made i to be Integer with the use of keyword int.

Lat us say, teacher instruct you to make use of multiple puts(), like:

puts("I will switch off lights");
puts("I will switch off fans");
puts("and i will also switch off AC");
puts(" when leaving room");

With further instruction, that each set of these four lines, MUST have two blank lines between them.

Can you achieve it?

Try, and discuss in Technical Forum of guru.gndec.ac.in

Index

PPS

Programming for Problem Solving

Compiling and running program by amending messages