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Download Maple Programming Guide - Numerical Relativity Group at UBC
Transcript
5.6 Flow Control • 187 > if 2 > 3 then print( "CONSEQUENT" ) else print( "ALTERNATIVE" ) end if; (5.27) The most general form of an if statement can have several conditions, corresponding consequents, and an optional alternative branch. This general form has the syntax: if condition1 then consequent1 elif condition2 then consequent2 .... else alternative end if in which there can be any number of branches preceded by elif. The effect of this general form of the if statement is to divert the flow of control into the first branch whose conditional expression evaluates to true. This means that the order of the elif branches can affect the behavior of the if statement. The branch introduced by else is optional. If it is present, and none of the earlier condition expressions evaluates to true, then control flows into the else branch. If it is not present, and none of the earlier condition expressions evaluates to true, then the flow of execution continues with the first statement following the entire if statement. > if 2 > 3 then print( "CONSEQUENT1" elif 3 > 4 then print( "CONSEQUENT2" elif 1 < 5 then print( "CONSEQUENT3" elif 2 < 5 then print( "CONSEQUENT4" else print( "ALTERNATIVE" end if; ) ) ) ) ) (5.28)
