Analysis of Structures - Baustatik-Info-Server

2.8. BRANCHES FOR DECISIONS Page 25Figure 2.2: Calculating the Factorial for a float2.8 Branches for DecisionsDecisions are made by the usage of the if statement. The if statement is defined as follows.if [boolean expression 1]:code block 1elif [boolean expression 2]:code block 2elif [boolean expression 3]:code block 3...elsecode block elseThe calculation of roots of a quadratic equation is a nice and simple example to show the application ofthe if statement. The quadratic equation is given bya · x 2 + b · x + c = 0 (2.8)If we want to solve the quadratic equation, we have to analyze the available cases. A general solutionmust handle the following cases.• constant casea = b = c = 0• linear casea = 0, b ≠ 0• quadratic casea ≠ 0• no solution casea = b = 0 and c ≠ 02.12.2011