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macOS C++ Compiler for Mac? HELP with xcode?

oxshannon said:
um still not that great. i dont understandwhat i should initialize x and y to. i looked in my book and the only example on the reference stuff is with the quadratic equation and i cant follow it what so ever. so its not looking too great. im really not sure what else im supposed to change here! i feel like im close though
Click to expand...

Post your code and state which 'x' and 'y' you're referring to.

I getting pissed at this forums posting interface. I keep trying to make a separate post form this one but since I'm the last poster it keeps appending.

It's both irritating and confusing!
 
now that i changed my initialization of variables (see my last edit) it isnt telling me it has to be initialized anymore.
 
Thanks for that!

oxshannon said:
Code: 
int main ()
{
	double x;
	double y; 
	double r; 
	double angle;

because in the example i have it doesnt show the & in the initialization. when i do this the program runs, but its still wrong. ie: if i input 3, it spits 3 back out. so i know im not done, but was this a good move? is the & not supposed to be in the main body?
Click to expand...

That part seems correct but post the full source.
 
Code: 
#include <iostream>
using namespace std; 
#include <cmath>

double polar (double &, double &, double, double);

int main ()
{
	double x;
	double y; 
	double r; 
	double angle;
	
	cout << "Enter two numbers for polar coordinates: ";
	cin >> r, angle; 

	polar (x, y, r, angle);

	cout << "The corresponding rectangular coordinates are (" << x << ", " << y << ")" << endl;
	
	return 0; 
}

double polar (double & x, double & y, double r, double angle) 
{
	x = r * cos (angle);
	y = r * sin (angle);
	
	return x;
	return y;
}

i feel like this should work!!! i dont know what im missing
 
I see! THe values are being return thru their references passed as parameter to the routine. There is no longer a need to explicitly 'return' anything!
 
lloyddean said:
I see! THe values are being return thru their references passed as parameter to the routine. There is no longer a need to explicitly 'return' anything!
Click to expand...

so i can remove the return in the function definition?

and does this main change the function prototype to void? since there will be no return?
 
lloyddean said:
It's just as easy to try as ask it!
Click to expand...

i removed return and changed to void, but when i input test case (3.5, 20) it still returns, 3.5 and 0 rather than the proper numbers :/

and i get this warning: polar.cpp:15:12: warning: expression result unused [-Wunused-value]
cin >> r, angle;
 
Code: 
#include <iostream>
using namespace std; 
#include <cmath>

void polar (double &, double &, double, double);

int main ()
{
	double x;
	double y; 
	double r; 
	double angle;
	
	cout << "Enter two numbers for polar coordinates: ";
	cin >> r, angle; 

	polar (x, y, r, angle);

	cout << "The corresponding rectangular coordinates are (" << x << ", " << y << ")" << endl;
	
	return 0; 
}

void polar (double & x, double & y, double r, double angle) 
{
	x = r * cos(angle);
	y = r * sin(angle);
	
}

thanks for your patience :D:D:D
 
The prototypes for cos and sin are already in your
Code: 
#include <cmath>

The point I was trying to make is that to test r=3.5 angle=20 degrees you need to input (20*(pi/180)) radians into sin and cos.

Also, check and see if your input values are being set properly. Are you operating on good input?

B
 
Last edited:
oxshannon said:
still confused :p lol so are you saying i dont need to change my code? just my input? how do i check if im operating on good input, i dont understand what that means
Click to expand...

How might you tell if the values you are operating on in your function are what you think provided as input? (Hint: use the debugger, or some kind of output?)

B
 
balamw said:
How might you tell if the values you are operating on in your function are what you think provided as input? (Hint: use the debugger, or some kind of output?)

B
Click to expand...

i really have no clue what youre talking about. sorry :confused::confused:
 
Maybe something similar to your

Code: 
cout << "The corresponding rectangular coordinates are (" << x << ", " << y << ")" << endl;

for r and angle instead of x and y could be useful somewhere?


----------
lloyddean said:
SHe working from the Terminal and a text editor!
Click to expand...

That's why I suggested the alternative. However gdb still works from the command line if you want it to. ;)

B
 
balamw said:
Maybe something similar to your

Code: 
cout << "The corresponding rectangular coordinates are (" << x << ", " << y << ")" << endl;

for r and angle instead of x and y could be useful somewhere?

B
Click to expand...

i have to follow the output that my professor gives us though.. so i cant add anything else in. and im still not sure i comprehend what youre talking about
 
Direct hint: Something is wrong with your cin.

You can add other debug output to make sure it is good and then take them out.

B
 
balamw said:
Direct hint: Something is wrong with your cin.

You can add other debug output to make sure it is good and then take them out.

B
Click to expand...

sorry forbeing so dumb, what could be wrong with my cin? this is the program from hell.

edit:

is this why im getting this warning?
polar.cpp:15:12: warning: expression result unused [-Wunused-value]
cin >> r, angle;
 
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