Temperature conversion

[kingfnie]

I am trying to write a program that will convert an array of temperatures to Celsius and display them with the Fahrenheit values. I have the program put together my problem comes when i try to convert the values to Celsius I was thinking the value would be something like (Fahrenheit -32) * (5/9) but i can never get it to work.

  // sample code




#include <iostream>
#include <string>

using namespace std;



int main(int argc, char** argv) {
	// variable declaration section
	const int ARRAY_SIZE = 7;
	string dayName[ARRAY_SIZE] = { "Mon", "Tue", "Wed", "Thur","Fri", "Sat", "Sun" };
	float dayTEMP[ARRAY_SIZE] = {65, 72, 44, 45, 66, 88, 99};
	
	//celsius array
	string dayNamei[ARRAY_SIZE] = { "Mon", "Tue", "Wed", "Thur","Fri", "Sat", "Sun" };
	float dayTEMPi[ARRAY_SIZE] = {65, 72, 44, 45, 66, 88, 99};

	
	
	// temp table
	for (int arrayIndex = 0; arrayIndex < ARRAY_SIZE; arrayIndex++)
	{
		cout << dayName[arrayIndex] << " Fahrenheit: "<< dayTEMP[arrayIndex] << endl;
		cout << dayNamei[arrayIndex] << " Celsisus: " << dayTEMPi[arrayIndex] << endl;
	}


	return 0;
}

[Repeater]

float tempInCelsius = (tempInFahrenheit - 32) * (5.0/9.0);

[kingfnie]

Ok so how would I implement that into my current code. Do I add it as part of my array ?

[malibor]

I would make a helper function that takes Fahrenheit array, and returns new Celsius array.
(even better using std::array or std::vector)
the function should do computation for each array index and store the result into a new array.

edit:
for example:

void GetCelsius(const float original[], float output[], const int& size)
{

	for (size_t i = 0; i < size; i++)
	{
		output[i] = (original[i] - 32) * (5.0 / 9.0);
	}
}

In your main dayTEMPi[ARRAY_SIZE] should be passed as second paramenter to function to initialize it with celsius values.

for example:
GetCelsius(dayTEMP, dayTEMPi, ARRAY_SIZE);

[MikeStgt]

my current code

First: dayNamei[] and dayName[] have the same content. Do you plan to change that one day in some future or would one array be enough?
Second: Did you read temperature in Farenheit? Then store only Farenheit values. To display °C compute it.

I suggest:

// sample code
#include <iostream>
#include <string>
using namespace std;

int main()
{
    // variable declaration section
	const int ARRAY_SIZE = 7;
	string dayName[ARRAY_SIZE] = { "Mon", "Tue", "Wed", "Thur","Fri", "Sat", "Sun" };
	float dayTEMP[ARRAY_SIZE] = {65, 72, 44, 45, 66, 88, 99};
	
	// temp table
	for (int arrayIndex = 0; arrayIndex < ARRAY_SIZE; arrayIndex++)
	{
		cout << dayName[arrayIndex] << " Fahrenheit: "<< dayTEMP[arrayIndex]
		                            << ", Celsisus: " << (dayTEMP[arrayIndex] - 32) * 5 / 9.0 << endl;
	}
//	return 0;
}

Result:

Mon Fahrenheit: 65, Celsisus: 18.3333
Tue Fahrenheit: 72, Celsisus: 22.2222
Wed Fahrenheit: 44, Celsisus: 6.66667
Thur Fahrenheit: 45, Celsisus: 7.22222
Fri Fahrenheit: 66, Celsisus: 18.8889
Sat Fahrenheit: 88, Celsisus: 31.1111
Sun Fahrenheit: 99, Celsisus: 37.2222

[kingfnie]

thank you guys so much I learned a lot in this thread my problem was how i was trying to add the code to execute things I kept trying to add it in the variable decloration setting I had tried the way above but but with two arrays and it was all messed up.

[kingfnie]

Ok new problem .. this guy is just trying to be an ass on purpose his instructions said nothing about using functions but once I submitted it he decided to be more difficult. Ok so I have done a new code

//Sample code

// second try yaaay



#include <iostream>
#include <string>

using namespace std;

//Call this function below to convert F to C.
float temperature_calc(float f)
{	
    float c;	
    c = (f-32) * 5/9;	
    
    return c;	
}
 


int main(int argc, char** argv) {
	// variable declaration section
	const int ARRAY_SIZE = 7;
	string dayName[ARRAY_SIZE] = { "Mon", "Tue", "Wed", "Thur","Fri", "Sat", "Sun" };
	float dayTEMP[ARRAY_SIZE] = {65, 72, 44, 45, 66, 88, 99};
	
	
	//temp table
	for (int arrayIndex = 0; arrayIndex < ARRAY_SIZE; arrayIndex++)
	{
		cout << dayName[arrayIndex] << " Fahrenheit: "<< dayTEMP[arrayIndex] << endl;
		                            //cant figure out what to call here to call function above
		
	}


	return 0;
}

[Repeater]

In C++, 5/9 is 0, because an int divided by an int gives an int.

If you want 5/9 to be 0.555556 , you need to do a float divided by an int.

http://cpp.sh/2r3lp

[dhayden]

Repeater's comment is very important. The issue frequently trips up beginners. But in your case, the code will work:
c = (f-32) * 5/9; actually evaluates as:
c = ((f-32) * 5) / 9; f is a float, so 32 gets promoted to float and f-32 is a float
Since f-32 is a float, 5 gets promoted and (f-32)*5 is a float
Since (f-32)*5 is a float, 9 gets promoted and ((f-32)*5)/9 is a float.

[Ganado]

kingfnie wrote:

//cant figure out what to call here to call function above

cout << dayName[arrayIndex] << " Celsius: "<< temperature_calc(dayTEMP[arrayIndex]) << endl;

PS: You probably would have gotten a faster response if you stated the actual problem in your post instead of it being hidden in a comment. Just sayin'.