Swift - 嵌套的 If 语句

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  简述

  在 Swift 4 中嵌套总是合法的 if-else 语句，这意味着您可以使用一个 if 要么 else if另一边 if 要么 else if 声明。
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  句法

  的语法 nested if 声明如下 -

  
  if boolean_expression_1 {
     /* Executes when the boolean expression 1 is true */
     
     if boolean_expression_2 {
        /* Executes when the boolean expression 2 is true */
     }
  }
  

  你可以嵌套 else if...else以与嵌套if语句类似的方式。
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  例子

  
  var varA:Int = 100;
  var varB:Int = 200;
  /* Check the boolean condition using if statement */
  if varA == 100 {
     /* If condition is true then print the following */
     print("First condition is satisfied");
     if varB == 200 {
        /* If condition is true then print the following */
        print("Second condition is also satisfied");
     }
  }
  print("Value of variable varA is \(varA)");
  print("Value of variable varB is \(varB)");
  

  当上面的代码被编译和执行时，它会产生以下结果 -

  
  First condition is satisfied
  Second condition is also satisfied
  Value of variable varA is 100
  Value of variable varB is 200