Built in functions (std, etc.) for converting Degrees to Radians?

[tmason]

Hello,

I have a simple question that I didn't find an answer to while googling.

Are there STD functions for converting degrees to radians and radians to degrees?

I know I can write my own but in the particular application I would like to use built-in ones for maintainability.

Thank you for your time.

[MiiNiPaa]

No, there is none.
In future, you can use reference to know about standard library content:

http://www.cplusplus.com/reference/ 
http://en.cppreference.com/w/

[Ganado]

I'll usually just have a constant variable called "toRadians" = Pi / 180.0 and another called "toDegrees" = 180.0 / Pi. Wouldn't even need a function call.
Then you can easily do cos(45*toRadians);

[ne555]

¿where did you get `Pi'?

I can only visualize a small set of angles, and those I already know their sin or cos, so I hate when applications ask me for degrees, that they will convert to radians, and compute their sin and cos to make a rotation.

[tmason]

Thanks everyone!

@ne555 the values are "defines" in Math.h

[MiiNiPaa]

tmason wrote:

@ne555 the values are "defines" in Math.h

Pi is not defined in math.h/cmath header. Some implementations might define it, but it is non-standard and unsupported/

[tmason]

I stand corrected; any include file where it is defined as standard or is it best to define it yourself in your own includes?

[Ganado]

Yeah I would just define it yourself.

¿where did you get `Pi'? ...so I hate when applications ask me for degrees
Yeah I just defined it myself, didn't mean to cause confusion.
The first thing that comes to my mind is an art program like photoshop or paint, much easier to ask the user for a degree than radian. I'm sure some programs let you specify if the user wants to use radians or degrees, of course.

[MiiNiPaa]

1) If you already using Boost, you can get Pi as boost::math::constants::pi<double>();
2) If you do not use boost, it is often better to define it yourself:

const double Pi = 3.14159265358979323846264; //constant expression
const double Pi = std::atan2(0, -1); //Calculated in runtime
const double Pi = std::acos(-1); 

[ne555]

> an art program like photoshop or paint, much easier to ask the user for a degree than radian.
¿In what operation? I can't seem to picture a case where I would want a box to write 42 degrees.
Would rather move a point, slide a bar, or pick an already done slope.
And in technical drawing, those weird angle measures would be calculated from other dimensions.

And for well know angles, 1/6, 1/4, 1/3 (pi implicit) are a lot more clear than 30, 45, 60.