{"id":346,"date":"2014-12-30T18:05:52","date_gmt":"2014-12-30T17:05:52","guid":{"rendered":"http:\/\/www.valcon.it\/pascal\/?p=346"},"modified":"2014-12-30T18:09:37","modified_gmt":"2014-12-30T17:09:37","slug":"selezioni-annidate","status":"publish","type":"post","link":"https:\/\/www.valcon.it\/pascal\/selezioni-annidate\/","title":{"rendered":"Selezioni annidate"},"content":{"rendered":"<p><img loading=\"lazy\" decoding=\"async\" class=\"alignright wp-image-70 size-full\" src=\"http:\/\/www.valcon.it\/pascal\/wp-content\/uploads\/if4.png\" alt=\"if4\" width=\"363\" height=\"469\" srcset=\"https:\/\/www.valcon.it\/pascal\/wp-content\/uploads\/if4.png 363w, https:\/\/www.valcon.it\/pascal\/wp-content\/uploads\/if4-116x150.png 116w, https:\/\/www.valcon.it\/pascal\/wp-content\/uploads\/if4-232x300.png 232w\" sizes=\"(max-width: 363px) 100vw, 363px\" \/>Le condizioni perch\u00e9 dei blocchi siano eseguiti a scapito di altri possono essere complicate&#8230;<\/p>\n<p>Procedi in modo <strong>top-down<\/strong> utilizzando <em>sempre<\/em> le etichette di inizio e fine blocco<\/p>\n<p><em>Top&#8230;<\/em><\/p>\n<pre>If A > 0 Then\r\n \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 (* ... da sistemare ... *)\r\n \u00a0 End\r\nElse\r\n \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 (* ... da sistemare ...*)\r\n \u00a0 End;<\/pre>\n<p><em>&#8230;down<\/em><\/p>\n<pre>If A > 0 Then\r\n \u00a0 Begin\r\n \u00a0 \u00a0 \u00a0If B > 0 Then\r\n \u00a0 \u00a0 \u00a0 \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 (* ... *)\r\n \u00a0 \u00a0 \u00a0 \u00a0 End\r\n\u00a0 \u00a0 \u00a0 Else\r\n \u00a0 \u00a0 \u00a0 \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 (* ... *)\r\n \u00a0 \u00a0 \u00a0 \u00a0 End;\r\n \u00a0 End\r\nElse\r\n \u00a0 Begin\r\n \u00a0 \u00a0 \u00a0If C > 0 Then\r\n \u00a0 \u00a0 \u00a0 \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 (* ... *)\r\n \u00a0 \u00a0 \u00a0 \u00a0 End\r\n  \u00a0 \u00a0 Else\r\n\u00a0\u00a0 \u00a0 \u00a0 \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 (* ... *)\r\n\u00a0\u00a0 \u00a0 \u00a0 \u00a0 End;\r\n\u00a0\u00a0 End;<\/pre>\n<p><em>&#8230; down<\/em><\/p>\n<pre>If A > 0 Then\r\n\u00a0 \u00a0Begin\r\n\u00a0 \u00a0\u00a0 \u00a0If B > 0 Then\r\n\u00a0 \u00a0\u00a0 \u00a0 \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Istr11;\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Istr12;\r\n\u00a0 \u00a0\u00a0 \u00a0 \u00a0 End\r\n\u00a0 \u00a0 \u00a0 Else\r\n\u00a0 \u00a0\u00a0 \u00a0 \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Istr21;\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Istr22;\r\n\u00a0 \u00a0\u00a0 \u00a0 \u00a0 End;\r\n\u00a0 \u00a0End\r\nElse\r\n\u00a0 \u00a0Begin\r\n\u00a0 \u00a0\u00a0 \u00a0If C > 0 Then\r\n\u00a0 \u00a0\u00a0 \u00a0 \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Istr31;\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Istr32;\r\n\u00a0 \u00a0\u00a0 \u00a0 \u00a0 End\r\n\u00a0 \u00a0 \u00a0 Else\r\n\u00a0 \u00a0\u00a0 \u00a0 \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Istr41;\r\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Istr42;\r\n\u00a0 \u00a0  \u00a0 \u00a0 End;\r\n\u00a0 \u00a0End;<\/pre>\n<p>Se l&#8217;uso delle istruzioni annidate risulta complesso \u00e8 consigliabile utilizzare delle selezioni esplicite per ogni singolo blocco di istruzioni a costo di espressioni logiche pi\u00f9 complesse&#8230;<\/p>\n<pre>If(A > 0) And (B > 0) Then\r\n \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 Istr11;\r\n\u00a0 \u00a0 \u00a0 Istr12;\r\n \u00a0 End\r\nElse If(A > 0) And (B < 0) Then\r\n \u00a0 Begin\r\n\u00a0 \u00a0 \u00a0 Istr21;\r\n\u00a0 \u00a0 \u00a0 Istr22;\r\n \u00a0 End\r\n...\r\n...<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Le condizioni perch\u00e9 dei blocchi siano eseguiti a scapito di altri possono essere complicate&#8230; Procedi in modo top-down utilizzando sempre le etichette di inizio e fine blocco Top&#8230; If A > 0 Then \u00a0 Begin \u00a0 \u00a0 \u00a0 (* &#8230; da sistemare &#8230; *) \u00a0 End Else \u00a0 Begin \u00a0 \u00a0 \u00a0 (* &#8230; da &#8230; <a title=\"Selezioni annidate\" class=\"read-more\" href=\"https:\/\/www.valcon.it\/pascal\/selezioni-annidate\/\" aria-label=\"Leggi di pi\u00f9 su Selezioni annidate\">Leggi tutto<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/posts\/346"}],"collection":[{"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/comments?post=346"}],"version-history":[{"count":3,"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/posts\/346\/revisions"}],"predecessor-version":[{"id":349,"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/posts\/346\/revisions\/349"}],"wp:attachment":[{"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/media?parent=346"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/categories?post=346"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.valcon.it\/pascal\/wp-json\/wp\/v2\/tags?post=346"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}