Comments on: 2.10 — Comprehensive quiz

By: Umbra

Umbra — Sun, 18 Dec 2011 07:39:17 +0000

I’ve stumbled upon this site on a mission to revitalize my 10-years dormant C++ coding avocation. I thoroughly enjoyed my experience to this point but could not hold back registering after I took this quiz.

While my answers correctly anticipated the solutions, I can’t help but wonder if the use of unsigned long int (for cents — reformatted to dollars and cents) isn’t more appropriate for a stock price variable, as the potential for rounding errors begin to creep in at the upper end of where inflated prices are heading.

:) j/k

great job!

By: xero

xero — Tue, 22 Nov 2011 10:57:25 +0000

My code for question number 4 is:
#include
double InputNumber()
{
using namespace std;
cout << "Insert the digit" <> fDigit;
return fDigit;

}

char InputOperand()
{
using namespace std;
cout << "Insert operator (+,-,*,/)" <> chOperator;
return chOperator;
}

void calculation()
{
calculator:
using namespace std;
double digitOne = InputNumber();
double digitTwo = InputNumber();
char operand = InputOperand();
if (operand==’+')
cout << "Sum of both the digits is " << (digitOne + digitTwo) << endl;
else
if (operand=='-')
cout << "Subtracting both digits results into " << (digitOne – digitTwo) << endl;
else
if (operand=='*')
cout << "Multiplying both digits results into " << (digitOne * digitTwo) << endl;
else
if (operand=='/')
cout << "Dividing both digits results into " << (digitOne / digitTwo) << endl;
else
cout << "You have inserted an invalid operator. Restart the Program" << endl;
}

int main()
{
calculation();
return 0;
}

By: zingmars

zingmars — Tue, 31 May 2011 17:26:24 +0000

1) stop using system(“Pause”). Google it and you’ll understand why. Seriously.
2) try using else if statements.

By: tux

tux — Tue, 31 May 2011 14:21:17 +0000

can anybody help me this code?

#include

using namespace std;

int main()
{

cout <> x;
cout <> y;
cout <> chUserInput;

if(chUserInput == ‘ + ‘)
cout << x << " + " << y << " is " << x + y << endl;
if(chUserInput == ' – ')
cout << x << " – " << y << " is " << x – y << endl;
if(chUserInput == ' * ')
cout << x << " * " << y << " is " << x * y << endl;
if(chUserInput == ' / ')
cout << x << " / " << y << " is " << x / y << endl;

system("pause");
return 0;
}

it will run but when i enter the numbers it will not print the results only "press any key to continue" but when i copy/paste the example of ALEX it will print the results… i'm a newbie and want to learn C++ coz itz a mind twister programming IMHO.thnx to ALEX for his great tutorials.

By: Dave_K

Dave_K — Wed, 18 May 2011 15:54:46 +0000

else if

In other words if you have:

if (x == y) //some code here else if (x == z) //some code here else //other code

By: Dave_K

Dave_K — Wed, 18 May 2011 15:42:53 +0000

So I made the program and probably made it entirely too complex however, I did it for the purpose of modularization. While I realize this program has a very simple result I’m trying to get in good coding habits. Here is my code, any suggestions? (Also I added a bit of functionality to the if statement after playing with it):
//Learncpp.com Ch2.10 Quiz question 4 /*Program will take 2 floating point numbers from the user, ask them for an operator (+, -, *, /) and then output the result of the mathematical operation.*/


#include "io.h"
int main()

{

	writeAnswer();
    return 0;

}
//I/O functions for the program
#include 
//Asks the user for the first number

double firstNumber()

{

	using namespace std;
	//Get floating point number from user.

	cout << "Enter a number (can be a decimal): ";

	double dFirstNum;

	cin >> dFirstNum;
	return dFirstNum;

}
//Asks the user for the second number

double secondNumber()

{

	using namespace std;
	//Get floating point number from user

	cout << "Enter another number (can be a decimal): ";

	double dSecondNum;

	cin >> dSecondNum;
	return dSecondNum;

}
//Asks the user for a mathematical operator

char enterOperator()

{

	using namespace std;
	//Get a mathematical operator from user (+, -, *, /)

	cout << "Enter an operator (+, -, *, /): ";

	char	chOperator;

	cin >>	chOperator;
	return chOperator;

}
//Outputs the answer to the console

void writeAnswer()

{

	using namespace std;
	//Get equation from user

	double	dFirstNum	= firstNumber();

	char	chOper		= enterOperator();

	double	dSecondNum	= secondNumber();
	//Check to make sure the equation is valid and output the answer

	if (chOper == '+')

		cout << dFirstNum << " + " << dSecondNum << " = " << dFirstNum + dSecondNum << endl;

	else if (chOper == '-')

		cout << dFirstNum << " - " << dSecondNum << " = " << dFirstNum - dSecondNum << endl;

	else if (chOper == '*')

		cout << dFirstNum << " * " << dSecondNum << " = " << dFirstNum * dSecondNum << endl;

	else if (chOper == '/')

		cout << dFirstNum << " / " << dSecondNum << " = " << dFirstNum / dSecondNum << endl;

	else

	{

		cout << "Invalid operator entry." << endl;

		writeAnswer();

	}

}
//I/O prototypes for program

#ifndef IO_H

#define IO_H
double	firstNumber();

double	secondNumber();

char	userOperator();

void	writeAnswer();

#endif

By: zingmars

zingmars — Fri, 13 May 2011 17:02:53 +0000

1) use doubles, not floats
2) use else if’s, makes the code to look less confusing. Also it’s probably the reason your code fails.

By: zingmars

zingmars — Fri, 13 May 2011 16:59:03 +0000

Today I learned that I like to make stuff more complicated than it should be.
Anyway, I found what seemed to be two mistakes in the 3rd exercise –
You wrote “a) unsigned char unAgeInYears;”, while it’s a char, and you said to use ‘n’ for int variables.

By: amirabbas

amirabbas — Thu, 21 Apr 2011 11:27:17 +0000

#include
#include
int main()
{
int a,b;
int s;
char ch;
cout<> a;
cin >> b;
cout<> ch;
s=(int)ch;
cout <<" a"< //if ((int)ch==42) cout<< (a*b);
//else if ((int)ch==43) cout<< (a+b);
//else if ((int)ch==45) cout<< (a-b);
//else if ((int)ch==47) cout<< (a/b);
switch(s)
{
case 94:cout<<(a^b);break;
case 37:cout< case 42:cout< case 43:cout< case 45:cout< case 47:cout< default : cout<> a;
return 0;
}

By: Dominator_X

Dominator_X — Mon, 07 Mar 2011 12:56:11 +0000

Hello! Why did you use in

01 #include
02
03 int main()
04 {
05 using namespace std;
06 cout <> dX;
09
10 cout <> dY;
13
14 cout <> chChoice;
17
18 if (chChoice == ‘+’)
19 cout << dX << " + " << dY << " is " << dX + dY << endl;
20 if (chChoice == '-')
21 cout << dX << " – " << dY << " is " << dX – dY << endl;
22 if (chChoice == '*')
23 cout << dX << " * " << dY << " is " << dX * dY << endl;
24 if (chChoice == '/')
25 cout << dX << " / " << dY << " is " << dX / dY << endl;
26
27 return 0;
28 }

Double instead of integer type?