CAD in Civil Engineering - Baustatik-Info-Server

Page 36 Computer Languages for Engineering - SS 13• a = 0 ∧ b ≠ 0Linear case, x = −c/b.• a ≠ 0Quadratic case,x 1 = 12a (−b + √ b 2 − 4ac).x 2 = 12a (−b − √ b 2 − 4ac).2.9.2.2 A Flow-Chart of the QuadSolverThe following flow chart shows all the case, which we have to handle. The algorithm is given for a realarithmetic, i.e. no complex data types are used. The relevant source code will be developed within thenext section.Startyes yes yesa = 0 b = 0 c = 0infinitsolutionsStopnononod = b 2 − 4 · a · cx = − c bStopno solutionStopd < 0yesx 1,2 = −b±i√ −d2·aStopnox 1,2 = −b±√ d2·aStop2.9.2.3 Quadratic Equation, Solver Implementation Fortran 66 likeThe first implementation in strict Forteran 66 shows the subsequent solution of the above discussedcases. Because the if statement can only process one statement, the inverse case should be checked tojump over the succeeding code. After the code block a further jump should be performed to the laststatement of the program.Listing 2.19: Implementation of a 66-Quad-Solver1 c quadratic equation2 c a*x**2 + b*x + c =3 c4 c a,b,c are arbitray input parameters5 c6 c explicit declaration should be done7 c8 c2345679 implicit none10 cE. Baeck