need help with coding

alielsaadi (31)
we're supposed to write a centimeter to inch/ inch to centimeter converter
and my if statements are not working im still a newbie, can someone please tell me what i did wrong? 



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#include <iostream>
using namespace std; 

void main()
{
	int nb;
	double value;
	double result;


	cout << ("1 for inch to centimeter conversion") << endl;
	cout << ("2 for centimeter to inch conversion") << endl;
	cout << ("please make a selection: ");
	cin >> nb;

	if ( nb=1 ){
		cout <<("please enter the value in centimeters: ");
		cin >> value;
		result= value*0.39370;
		cout << value << (" centimeters = ") << result << endl;
	}
	else if ( nb=2 ) {
		cout <<("please enter the value in inches: ");
		cin >> value;
		result= value/0.39370;
		cout << value << (" centimeters = ") << result << endl;
	}
	else 
		cout <<(" wrong input ") << endl;



		
	system ("pause");

}


Smac89 (1727)
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if ( nb == 1 )
...
else if ( nb == 2 )
alielsaadi (31)
thank you!
gingy (37)
Well, someone already explained the problem. To explain that further, from what I understand, most programming languages treat a single equals sign as if you're setting something equal to what follows the equals sign. However, a double equals sign signifies a test for that condition to be equal.
alielsaadi (31)
thank you guys,
does the code look good?
mutexe (2372)
you are printing "centimeters =" in both cases.
it's best to initialise variables e.g.
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        nt nb = 0;
	double value = 0.0;
	double result = 0.0;

and there's duplicate code that could be refactored.
dont use using namespace std;
and i wouldnt use system("pause").

looks ok though :)

edit: wait a minute.. i dont think your conversion is right.
I chose 1 (inch to centimetre)
I chose 1 again (i.e. give me 1 inch in centimetres)
answer = 0.3937

Which is wrong as there's about 2 and half cm in an inch isn't there?

yea it's the other way around.
change:
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	cout << ("1 for inch to centimeter conversion") << endl;
	cout << ("2 for centimeter to inch conversion") << endl;

to
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        cout << ("1 for centimeter to inch conversion") << endl;
	cout << ("2 for inch to centimeter conversion") << endl;
Last edited on
xenovia12 (658)
because you are using assignment operator instead of comparison operator.
alielsaadi (31)
Thank you very much mutexe. code is fixed. you guys are awesome.
mutexe (2372)
Cool.
On the refactoring front, i just meant reduce some duplicate code. Something like this maybe:
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#include <iostream>
#include <string>

int main()
{
	int choice = 0;
	double value = 0.0;
	double result = 0.0;
	const double conversion = 0.39370;
	std::string units = " centimeters = ";

	std::cout << ("1 for centimeter to inch conversion") << std::endl;
	std::cout << ("2 for inch to centimeter conversion") << std::endl;
	
	std::cout << ("please make a selection: ");
	std::cin >> choice;

	std::cout << ("please enter the value to convert: ");
	std::cin >> value;

	if (choice == 1)
	{			
		result = value*conversion;				
	}
	else if (choice == 2)
	{
		result = value / conversion;	
		units = " inches = ";
	}
	else
	{
		std::cout << (" wrong input ") << std::endl;
	}

	std::cout << value << units << result << std::endl;

	return 0;
}
alielsaadi (31)
thank you this looks much better.
may i ask why use std::cout when we can declare using namespace std;?
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