格式

if (<#condition#>) {
        <#statements#>
    }    
    switch (<#expression#>) {
        case <#constant#>:
            <#statements#>
            break;
            
        default:
            break;
    }- (void)applicationDidEnterBackground:(UIApplication *)application {
    
}    while (<#condition#>) {
        <#statements#>
    }- (void)applicationDidEnterBackground:(UIApplication *)application {
    
}typedef NS_ENUM(NSInteger, UIButtonType) {
        UIButtonTypeCustom = 0,                         // no button type
        UIButtonTypeSystem NS_ENUM_AVAILABLE_IOS(7_0),  // standard system button
        
        UIButtonTypeDetailDisclosure,
        UIButtonTypeInfoLight,
        UIButtonTypeInfoDark,
        UIButtonTypeContactAdd,
        
        UIButtonTypeRoundedRect = UIButtonTypeSystem,   // Deprecated, use UIButtonTypeSystem instead
    };@property(nullable, nonatomic,copy)   NSString           *text;