int sds_getangle (const sds_point firstpt, const char *prompt, double *answer);
Ask the user to specify an angle.
This function pauses to get an angle from the user. You can prompt the user to specify an angle numerically, or by picking points.
The argument firstpt represents the first point of the angle. It may be null. When null, the user enters the angle itself, using the current units for angles.
If given a starting point (firstpt), the user picks another point to define a rubber-band line, and sds_getangle determines the counter-clockwise angle between the current zero direction (as set in ANGBASE) and the rubber-band line.
The prompt argument represents a command-line prompt requesting that the user specify or pick an angle. This argument may be null.
The answer argument represents the angle specified by the user, counter-clockwise from the zero direction, expressed in radians (regardless of the current units for angles).
This function returns one of the following: RTCAN, RTERROR, RTKWORD, RTNONE, or RTNORM.
NOTE This functions read ANGBASE to find the 0-angle direction. If you prefer the 0-angle fixed in the east or 3 o'clock direction, use the sds_getorient function.
sds_getpoint(NULL,"\nFirst point: ",firstpt);
sds_getangle(point1,"\nSecond point: ",&answer);
sds_printf("\nThe angle is %f radians.",answer);
Tell me about...
Programming Overview of SDS (Solutions Development System)