Swift if statement

Swift conditional statement

If a Boolean expression followed by a statementby the one or more statements.

grammar

Swift languageif the syntax of the statement:

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

If the Boolean expression istrue, the if statement within a block of code will be executed.If the Boolean expression isfalse, if the first set of codes after the statement (after the close parenthesis) will be executed.

flow chart

Examples

import Cocoa

var varA:Int = 10;

/* 检测条件 */
if varA < 20 {
    /* 如果条件语句为 true 执行以下程序 */
    print("varA 小于 20");
}
print("varA 变量的值为 \(varA)");

When the above code is compiled and executed, it produces the following results:

varA 小于 20
varA 变量的值为 10

Swift conditional statement