Swift if ... else statement

Swift conditional statement

After aif statement with an optional else statement,else statement executes the Boolean expression is false.

grammar

Swift language syntaxif ... else statement:

if boolean_expression {
   /* 如果布尔表达式为真将执行的语句 */
} else {
   /* 如果布尔表达式为假将执行的语句 */
}

If the Boolean expression istrue, then the code ifthe execution block. If the Boolean expression isfalse, then the code within the elseblock executed.

flow chart

Examples

import Cocoa

var varA:Int = 100;

/* 检测布尔条件 */
if varA < 20 {
   /* 如果条件为 true 执行以下语句 */
   print("varA 小于 20");
} else {
   /* 如果条件为 false 执行以下语句 */
   print("varA 大于 20");
}
print("varA 变量的值为 \(varA)");

When the above code is compiled executed, it will produce the following results:

varA 大于 20
varA 变量的值为 100

Swift conditional statement