SGN Function Programming Example
 
The following program calculates and prints the solution for the input
quadratic (or second-degree) equation. The program uses the sign of a
test expression to determine how to calculate the solution.
 
CONST NoRealSoln=-1, OneSoln=0, TwoSolns=1
' Input coefficients of quadratic equation:
' ax^2 + bx + c = 0.
INPUT;"a = ",   A
INPUT;",  b = ",B
INPUT ",  c = ",C
Test = B^2 - 4*A*C
SELECT CASE SGN(Test)
   CASE  NoRealSoln
      PRINT "This equation has no real-number solutions."
   CASE  OneSoln
      PRINT "This equation has one solution: ";
      PRINT -B/(2*A)
   CASE  TwoSolns
      PRINT "This equation has two solutions: ";
      PRINT (-B + SQR(Test))/(2*A) " and ";
      PRINT (-B - SQR(Test))/(2*A)
END SELECT
 
Sample Output
 
This equation has two solutions:  .6666667      -.25