Comments on: 3.2 — Arithmetic operators

By: profanegod

profanegod — Fri, 16 Dec 2011 05:06:05 +0000

bacia – it’s pretty easy to formulate best guesses on square roots. It has to do with averaging the quotients and guesses. Here’s a mathematical example.

Find sqrt(9):

Guess1: 1 9/1 = 9
Average1: (9+1)/2 = 5

Guess2: 5 9/5 = 1.8
Average2: (5+1.8)/2 = 3.4

Guess3: 3.4 9/3.4 = 2.647
Average3: (2.647+3.4)/2 = 3.0235

Guess4: 3.0235 9/3.0235 = 2.977
Average4: (3.0235+2.977)/2 = 3.00025

As you can see the answer for principal roots by this method aren’t as clean as they can be. But this process can be done on a computer with a high degree of precision after only a few iterations. Pretty much all you will need is a for or while loop (or recursive procedure), and the + and / operators.

By: bacia

bacia — Fri, 02 Dec 2011 16:10:11 +0000

Unfortunately I can’t make a program which solves quadratic equations without square roots or powers because the quadratic formula uses a square root. bummer

By: bacia

bacia — Fri, 02 Dec 2011 15:41:53 +0000

Are there operators for percents, powers, and roots?

By: RobP

RobP — Tue, 20 Sep 2011 15:53:43 +0000

Here’s my attempt at the even/odd program. Works pretty well. Side effects may include nausea, vomiting, heartburn, burning urination, and the desire to consider Rick Perry a valid presidential candidate. Ask your doctor if RobP’s solution is right for you.

// Workbench.cpp : Space to test snippets or programs that don’t need to be saved.
#include “stdafx.h”
#include

int main()
{
using namespace std;

int x;
cout << "Enter a number:" <> x;
if (x % 2 == 0)
cout << "You entered " << x << " which is even." << endl;
else cout << "You entered " << x << " which is odd." << endl;

return 0;
} // end of main()

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By: C++ Tutorial and Online Ebook

C++ Tutorial and Online Ebook — Wed, 30 Jun 2010 01:10:16 +0000

[...] 3.2 Arithmetic operators [...]

By: Kush

Kush — Tue, 01 Jun 2010 09:09:16 +0000

In your code, I presumed your casting was done to prevent errors, which occurs when a character is enetered when we ask for integer.
It generally crashed out programs… and I never knew how to get around it…
so, a little help in this program would be appreciated.

By: Stephan

Stephan — Tue, 16 Mar 2010 08:48:45 +0000

Just an aside.

I’m using Code::Blocks and I try out many of the examples of code offered up by contributors (excellent stuff – teaches me loads of what not to do . . . ;-)) and examples in the tutorials.
I noticed that the terminal window says “Process returned 0 execution time : 3.102 s(or what ever)” Yet the program seems to be instant (certainly not X seconds) . . . Just curious.

Prince of Darkness
Me + Electrickery = Smoke ;-)

By: Random C++ learner

Random C++ learner — Sun, 07 Feb 2010 00:18:36 +0000

#include 


int main()
{
    using namespace std;
    cout << "Make 100 by adding a number to 23: ";
    double dX;
    cin >> dX;

    cout << "23 + " << dX << " Makes " << 23 + dX << endl;

    if (dX == 77)

    cout << "Congratulations you can do basic math." << endl;

    else

    cout << "\aoh dear, i hope you were testing the else statement..." << endl;

    return 0;
}

if the

 if (dX == 77)

is not bracketed, then it does not know what to check/ search for, and therefore won't compile. Although by now, you probably know why anyway. but a bit of practice in explaining anyway... every little helps.