Comments on: 5.3 — Switch statements

By: C++_4_fun

C++_4_fun — Sun, 15 Jan 2012 22:12:46 +0000

Sorry, I’m not sure why some of the code is still missing. Any suggestions?

By: C++_4_fun

C++_4_fun — Sun, 15 Jan 2012 22:11:18 +0000

?? Somo of my code was missing…
The main section should have read

int _tmain(int argc, _TCHAR* argv[])
{
	using namespace std;
	cout <> x;
	cout << endl <> y;
	cout << endl <> chOperator;
	Calculate(x, y, chOperator);
	cout << "The answer is: " << endl << Calculate(x, y, chOperator);

	return 0;
}

By: C++_4_fun

C++_4_fun — Sun, 15 Jan 2012 22:08:12 +0000

Hi, I tried to write a program using the function in the quiz to do basic calculation with no success. I'm not sure what I'm doing wrong but when I try to print the value returned to Calculate(x, y, chOperator) by the arguments in the switch I get gibberish. The code is below. Any advice is appreciated.

#include "stdafx.h"
#include
using namespace std;

int Calculate(int x, int y, char chOperator)
{
	switch (chOperator)
	{
	case '+':
			return x + y;
			break;
	case '-':
			return x - y;
			break;
		case '*':
			return x * y;
			break;
		case '/':
			return x/y;
			break;
	}
}

int _tmain(int argc, _TCHAR* argv[])
{
	using namespace std;
	cout <> x;
	cout << endl <> y;
	cout << endl <> chOperator;
	Calculate(x, y, chOperator);
	cout << "The answer is: " << endl << Calculate(x, y, chOperator);
	
	return 0;
}

By: zingmars

zingmars — Tue, 19 Jul 2011 11:19:29 +0000

The value would be correct, though everything after the comma would be removed.

By: SelfExplanatory

SelfExplanatory — Tue, 12 Jul 2011 17:15:25 +0000

In your solution for the quiz, wouldn’t (case ‘/’: return nX / nY) use integer division and return an incorrect value?

By: Groovychicken

Groovychicken — Wed, 23 Mar 2011 04:29:55 +0000

#include "stdafx.h"
#include 
#include 

void CalculateEquation(int nX, char chX, int nY)
{	
	using namespace std;

	switch(chX)
	{
		case('+'):
			cout << "The result of: " << nX << " " << chX << " " << nY << " is " << nX + nY << endl;
			break;
		case('-'):
			cout << "The result of: " << nX << " " << chX << " " << nY << " is " << nX - nY << endl;
			break;
		case('*'):
			cout << "The result of: " << nX << " " << chX << " " << nY << " is " << nX * nY << endl;
			break;
		case('/'):
			cout << "The result of: " << nX << " " << chX << " " << nY << " is " << nX / nY << endl;
			break;
		default:
			cout << "ERROR!" << endl;
			exit(0);
	}
}
	
int main()
{
	using namespace std;

	cout <> nX;
	cout << "You have entered: " << nX << " as your first integer. " << endl;

	cout <> chX;
	cout << "You have entered: " << chX << " as your mathematical operator. " << endl;

	cout <> nY;
	cout << "You have entered: " << nY << " as your second integer. " << endl;

	CalculateEquation(nX,chX,nY);

	return 0;
}

By: buffpony

buffpony — Thu, 09 Dec 2010 23:32:59 +0000

Actually forget that…. i fixed it. it was stupid. now i get the error when the program runs. it lets me enter numbers and operations, but crashed when performing them.

By: buffpony

buffpony — Thu, 09 Dec 2010 23:28:20 +0000

this code gives me the error: “Calculate cannot take one argument. What should i do?
#include
using namespace std;
int num1, num2;
char opp;
int Calculate(int num1,int num2, char opp)
{
switch(opp)
{
case ‘+’ || ‘plus’:
return num1+num2;
case ‘-’:
return num1-num2;
case ‘*’:
return num1*num2;
case ‘/’:
cout << "The first number is didided by the second";
return num1/num2;
default:
cout << "Error-program will exit";
exit(1);
}
}
int main()
{
cout <> num1;
cin >> num2;
cout << "Please Enter an opperation symbol: " <> opp;
Calculate(opp);
}

By: Jesper

Jesper — Sat, 02 Oct 2010 10:11:17 +0000

Hi Alex

I want to say that i love these tutorials you’ve made. I’ve been away from
c++ for some years and I needed a brush-up and this is just perfect. Great job!!
I have something to add to this section on the switch-case construct though.
The real reason why there is two ways to achieve the same thing i.e. if-elseif-else and switch-case
is because of execution-speed. if-elseif-else will always execute in linear time while switch-case
is implemented using a jump-table meaning it will execute in constant time. Though the jump-table
will only be used if the case-values are not spread out too far, because that would make the
jump-table too big.
So if it is possible you should always use switch-case and keep switch-values in the low range.

By: Compiler

Compiler — Sat, 04 Sep 2010 20:39:17 +0000

I tried to call the function this way:
int main()
{
Calculate(); //Didnt work, calculation doesnt take zero arguments
Calculate(int x,int y, char Operand); //didnt work either
return 0;
}