haxorDelite:
following you bro keep it up, but that "cout" am lost there oo

zyzxx:
bro u are a Gud teacher.
Av really learn a lot thanks
Following u bumper to bumper

Ezechinwa:


my brother, thank you jare, , this is my first out of many write ups on nairaland... i really appreciate it alot...

cout is a command to display stuff on screen/ output device...

for example,

cout << " anything you write here will show on screen ";

my main format is this, you must write the double arrow like dis << for cout and like dis >> for cin...

irrespective of the content, you must end it with semicolon ;

also see,

int nairaland ; // variable
nairaland = 4 ;

cout << nairaland ;

notice: from the second example, the output will not be nairaland but 4, becus nairaland is just a variable holding a valve which is 4...

conclusion... when displaying comments add ","... but when displaying the valve of a variable put that variable inside...

remember cpp is case sensitive, i mean capital letter is not the same as small letter...

example

int williams ;

williams is not the same as Williams...

thank you for following.. i do appreciate....

Ezechinwa:
please guys, i need more comments, more sharing, more questions and suggestions... thank you
note: am using blue text format because am a chelseafc fan lmao.........


OUTLINE....

hmm, just as we did to the first problem, we repeat again... writing an outline helps a lot in building programs....

let me break that problem down, the formula is

F= K(Q1*Q2)/R^2 OR
F= K(Q1*Q2)/(R*R)

WHERE

F= FORCE (NEWTON) (N)
K=CONSTANT ( assume is on air) (9.0 x 109 N • m*m / C*C)
Q1= CHARGE OF THE FIRST FIRST PARTICLE unit Coulombs (C)
Q2= CHARGE OF THE SECOND PARTICLE unit coulombs (C)
R= RADIUS/ DISTANCE BETWEEN CHARGES...( m^2)

*1 Aim: Program able to find the magnitude of the force of attraction between two bodies..
*2 Header files: suitable header files includes

#include <math.h> ( because we might need some mathematical operations)
#include <cstdio>
#include < iostream> ( because we require our program to get input/information from the user..

*3 NATURE: we need to ensure that the units are correct and complete, we can solve this problem breaking down into numerator(constant multiplying the product of charges and denominator( radius raise to power 2)...

*4 INPUTS : this program will requires 3 inputs from the user, note ( k is a constant and wont change, it will just sit there laughing lmao), ( but the main input are (Q1,Q2 , AND R).


*5 OUTPUT(S): this program will require just one major output which is "F=force"

*6 MATHEMATICAL SIGNS REQUIRED: from the nature of the problem, we can find four (4) signs namely ( Equal sign , pair of bracket, multiplication and as well division..)

*7 VARIABLE TYPE : " double" WILL BE VERY SUITABLE, DON'T USE "int" ( to avoid truncation error)...

*8 UNITS: it is important to ensure the units are correct.... to make this program simple lets assume no conversion where to be needed)......



what you see is just a mere outline, gives a feasibility study of what our program entails....
i will post solution as soon i get five (5) comments from the new or existing followers.......









Wow!!! This is awesome,i am really enjoying this ur tutorial.U r a genius,pls keep this tread alive,am following bumper to bumper.Tnx a million.

haxorDelite:
I got a question, can one build a web app with c++

Ezechinwa:
[color=#006600]

hope you guys didn't miss me that much, lol, well, so far, we have dealt with only one example... but now, we have another tactical problem on our hands...

we have just an outline, so lets apply it...
tools to solve this problem..

1. get a calculator / use your mobile phone.
2. switch on your pc, and open ur compiler.
3. get a cup of tea, relax and enjoy..

note:: look carefully at the constant K, it has a valve of 9 * 10 ^ 9.. prononced ( nine times ten raise to the power of 9).., we also assumed that our user won't enter a wrong unit, hence no conversion needed....
therefore K=constant= 9,000,000,000 n*m*m/c*c....

pls if that valve isnt correct, you can correct me
... i crammed dat formula since my sec school days.. lol..

note: as young programmers, it is a very good habit to have a small book, where u can write very important codes for future use ...

also note: if you only read this tutorial without practising it yourself , then your bound to forget... as programmers, you must practise what you learn... it will sink into your memory.. thank you.


having these apparatus in place, let's proceed....

solution...

// let's introduce suitable header files below...Part 1

1 #include <iostream>
2 #include <cstdio>
3 #include <math.h>






// let's start program flow, declaring main...Part 2

4. using namespace std ;
5. int main ()
6. {





// we have declared the start of program flow, its
//time to declared all our variables.... Part 3


7. double F ;
// output force

8. double Q1 ;
// input first charge

9. double Q2;
// input second charge

10. double R ;
// Input distance





// lets declare the constanst K.. Part 4.

11. double K = 9000000000;
// this valve will remain permanent... remember its a constant..







// Part 5 .. lets ask the user some questions

12. cout << " What is the valve of the first charge ( in columbs) : " ;
13. cin >> Q1;

14. cout << " What is the valve of the second charge ( in columbs) : " ;
15. cin >> Q2;

16. cout << "What is the valve of the distance ( in meters) : " ;
17. cin >> R;





// Let's break it first into numrator..Part 6.

18. double numurator ;
// variable for the numerator

19. numurator = ( Q1 * Q2 * K) ;
// your done with this aspect.. move now to denominator.






// Let's break the other part... denominator .. part 7...

20. double denominator ;
// variable for lower part of formula..

21. denominator = ( R * R) ;
// your done with this aspect..







// part 8... lets compile part 6 and 7...

22. F = ( numurator) / ( denominator) ;
// vola.. that's your force..





// finally, part 9.. produce results..

23. cout << " From the given information provided by you, the force of attraction between two bodies is : ";

24. cout << " Force is equal to : " ;
25. cout << F ;
26. cout << " unit is in ( Newton) " ;



// sign out...

27. system ( "PAUSE" ;
28. return 0;

}

Ezechinwa:




I implore you to test this codes... i will explain where neccesary... thank you.

swscorpio:
Please bro,which type of programming language use a word " echo " whenever we want it to display that output,i use to c it on Linux programs.Tnx

Ezechinwa:


yes it can, but its not suitable for this kind of tasks.. most common tools are java.. php.. but c++ , not dat in use..

haxorDelite:
owk thank you

Ezechinwa:
GUYS PLS COME UP WITH A PROBLEM, LETS BREAK IT DOWN TOGETHER.....

swscorpio:


Hi bro,Pls is that possible to write a program that will detect every person that login to my system(Redhat 6)?

zyzxx:
U rock bro

Ezechinwa:


Thanks... Bro... Did u run d code

Ezechinwa:


Its very possible, most websites use such facility, for example gmail, Facebook... Etc ( user authenticity) ,,, I will make more research and share whatever I find...

By d way, did you try out the second example?...

Ezechinwa:
..... Part 3..... continues....

LET'S begin... relax... do not cram but practise,,, And Encourage me...

INTRODUCTION TO CPP...


As promised earlier, am going to skip unrelevant stuffs about CPP... but for reference sake you can read up the following online.. you can use "google.com"

1. history of cpp
2. important of learning cpp
3. why you require a compiler, functions of a compiler.. etc.

as i posted earlier the tools required, am now going to post the mindset/techniques needed to venture in programning with Cpp...

1. Using comments "//" to make your codes readable and traceable .. let me explain...

there are many ways to put comments in your programs, but as a beginner using just "//" will do just fine...

for example.. we intend writing a program that sums two numbers??

imaging the following "scenarios "
(
case 1

int a;
int b;
int c;

c=a+b;
...

)
(
case 2

// program that adds two numbers

int a ; // first number
int b; // second number
int c; // variable rep output

c=a+b; // output of sum off two numbers.
...
)

from the about cases, but programs will run correctly, but case 1 is done by a dirty programmer and it will be hard to understand his work...

but case 2, is a well mapped program and can easily be readable and tracable as well...

it is important to note that anything writing after the // " would be ignored by the compiler ( also called Whitespaces)..


Nb.. its 4:24am, so am off to bed, i promise to update from here tomorrow.... once again thanks...

to be continued...

haxorDelite:
Bro can we combine javascript with it, for example => after inserting something in a field it opens automatically before one press opens

Ezechinwa:



note: from now, i will update this trend using a red color format...i proceed..
So far, we have looked into few foundations of C++, like the proper implementation of semicolons, brackets etc, in case your just tuning in, you haven't missed that much, just go back and read from the beginning..

Part 3... continues..

4. Header files and directives...

hmm, you want to write a program ( maybe solve a problem, lets say mathematical in nature) , it is important to add "HEADER FILES" using a directive "#include < header file> ..
don't get overwhelmed, let me explain what i mean, there are lots of "Header files" in cplusplus ( and you are not required to know all of them ), these files have a function to play in the program your building..
furthermore, the files are added to the program using a directive #include. you still don't get it?, OK, consider the two concepts we are discussing here namely "directives" and " header files" relate them to this example, assuming your giving an assignment in mathematics ( " to find the area of a square", of course you will go home and apply the formula "AREA= LENGTH * WIDTH" then return the result which is "AREA" to your teacher isn't it? now see ,

the "HEADER FILE" = FORMULA ( which is Area= length * width)
the Directive( #include) = YOU "applying the formula to the problem" ...

I will share with you few header files for beginners below,
"#include <stdio.h> " //will make the compiler to include the contents of standard header file
"#include <iostream>" // basically tells the compiler: i need input and output..
"#include <math.h> // to preform some mathematical operations, you need this library..

note:: please bear with me, i will get my laptop repaired soon, for now, am typing with a phone.. thank you..

picasso4u:

Ezechinwa, u re really doing a good job here. keep it up and God will increase ur knowledge.
what is d function of d quotation mark(" b4 d directive

Ezechinwa:
hello great minds... we are back again , what you saw in my previous posts were programs that can't make decisions...

so, later on today, i will show you how to develop programs that can make decision...

i haven't used variable types like boolean & string... so far, i will find problems needing such in future....

so later tonight... we move futher, for now i don't think my boss will find it funny seeing me posting rather dan working.. lol.. so, later guys...