Circles of given radius through two points: Difference between revisions

Content added Content deleted
(Added Delphi example)
m (→‎{{header|REXX}}: added/changed whitespace and comments, used a template for the output sections.)
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=={{header|REXX}}==
=={{header|REXX}}==
{{trans|XPL0}}
{{trans|XPL0}}

<br>The REXX language doesn't have a &nbsp; '''sqrt''' &nbsp; function, &nbsp; so one is included below.
<br>The REXX language doesn't have a &nbsp; '''sqrt''' &nbsp; function, &nbsp; so one is included below.
<lang rexx>/*REXX pgm finds two circles with a specific radius given two (X1,Y1) & (X2,Y2) points*/
<lang rexx>/*REXX pgm finds 2 circles with a specific radius given 2 (X1,Y1) and (X2,Y2) ctr points*/
@.=; @.1= 0.1234 0.9876 0.8765 0.2345 2
@.=; @.1= 0.1234 0.9876 0.8765 0.2345 2
@.2= 0 2 0 0 1
@.2= 0 2 0 0 1
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say ' ════════ ════════ ════════ ════════ ══════ ════════ ════════ ════════ ════════'
say ' ════════ ════════ ════════ ════════ ══════ ════════ ════════ ════════ ════════'
do j=1 while @.j\==''; parse var @.j p1 p2 p3 p4 r /*points, radii*/
do j=1 while @.j\==''; parse var @.j p1 p2 p3 p4 r /*points, radii*/
say f(p1) f(p2) f(p3) f(p4) center(r/1, 9) "───► " 2circ(@.j)
say fmt(p1) fmt(p2) fmt(p3) fmt(p4) center(r/1, 9) "───► " 2circ(@.j)
end /*j*/
end /*j*/
exit /*stick a fork in it, we're all done. */
exit 0 /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
2circ: procedure; parse arg px py qx qy r .; x=(qx-px)/2; y=(qy-py)/2
2circ: procedure; parse arg px py qx qy r .; x= (qx-px)/2; y= (qy-py)/2
bx=px + x; by=py + y; pb=sqrt(x**2+y**2)
bx= px + x; by= py + y
pb= sqrt(x**2 + y**2)
if r = 0 then return 'radius of zero yields no circles.'
if r = 0 then return 'radius of zero yields no circles.'
if pb==0 then return 'coincident points give infinite circles.'
if pb==0 then return 'coincident points give infinite circles.'
if pb >r then return 'points are too far apart for the specified radius.'
if pb >r then return 'points are too far apart for the specified radius.'
cb=sqrt(r**2 - pb**2); x1=y * cb / pb; y1=x * cb / pb
cb= sqrt(r**2 - pb**2); x1= y * cb / pb; y1= x * cb / pb
return f(bx-x1) f(by+y1) f(bx+x1) f(by-y1)
return fmt(bx-x1) fmt(by+y1) fmt(bx+x1) fmt(by-y1)
/*──────────────────────────────────────────────────────────────────────────────────────*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
f: arg f; f= right( format(f, , 4), 9); _= f /*format # with 4 dec digits*/
fmt: arg f; f= right( format(f, , 4), 9); _= f /*format # with 4 dec digits*/
if pos(.,f)>0 & pos('E',f)=0 then f= strip(f,'T',0) /*strip trailing 0s if .& ¬E*/
if pos(.,f)>0 & pos('E',f)=0 then f= strip(f,'T',0) /*strip trailing 0s if .& ¬E*/
return left( strip(f, 'T', .), length(_) ) /*strip trailing dec point. */
return left( strip(f, 'T', .), length(_) ) /*strip trailing dec point. */
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do j=0 while h>9; m.j=h; h=h%2+1; end /*j*/
do j=0 while h>9; m.j=h; h=h%2+1; end /*j*/
do k=j+5 to 0 by -1; numeric digits m.k; g=(g+x/g)*.5; end /*k*/; return g</lang>
do k=j+5 to 0 by -1; numeric digits m.k; g=(g+x/g)*.5; end /*k*/; return g</lang>
{{out|output}}
{{out|output|text=&nbsp; when using the default inputs:}}
<pre>
<pre>
x1 y1 x2 y2 radius circle1x circle1y circle2x circle2y
x1 y1 x2 y2 radius circle1x circle1y circle2x circle2y
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