Roots of a quadratic function: Difference between revisions
→{{header|Phix}}
m (→version 1: simplified expressions in the subroutine and also the function, added an output case to show different formatting for another REXX.) |
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Line 1,554:
Roots for 1, 0, -4 => (2, -2)
Roots for 1, -1000000, 1 => (999999.999999, 1.00000761449337e-06)</pre>
=={{header|Phix}}==
{{trans|ERRE}}
<lang Phix>procedure solve_quadratic(sequence t3)
atom {a,b,c} = t3
atom d = b*b-4*a*c, f
string s = sprintf("for a=%g,b=%g,c=%g",t3), t
sequence u
if abs(d)<1e-6 then d=0 end if
switch sign(d) do
case 0: t = "single root is %g"
u = {-b/2/a}
case 1: t = "real roots are %g and %g"
f = (1+sqrt(1-4*a*c/(b*b)))/2
u = {-f*b/a,-c/b/f}
case-1: t = "complex roots are %g +/- %g*i"
u = {-b/2/a,sqrt(-d)/2/a}
end switch
printf(1,"%-25s the %s\n",{s,sprintf(t,u)})
end procedure
constant tests = {{1,-1E9,1},
{1,0,1},
{2,-1,-6},
{1,2,-2},
{0.5,1.4142135,1},
{1,3,2},
{3,4,5}}
for i=1 to length(tests) do
solve_quadratic(tests[i])
end for</lang>
<pre>
for a=1,b=-1e+9,c=1 the real roots are 1e+9 and 1e-9
for a=1,b=0,c=1 the complex roots are 0 +/- 1*i
for a=2,b=-1,c=-6 the real roots are 2 and -1.5
for a=1,b=2,c=-2 the real roots are -2.73205 and 0.732051
for a=0.5,b=1.41421,c=1 the single root is -1.41421
for a=1,b=3,c=2 the real roots are -2 and -1
for a=3,b=4,c=5 the complex roots are -0.666667 +/- 1.10554*i
</pre>
=={{header|PicoLisp}}==
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