how to get print command in salesforce

normally in c or c ++ we are using p开发者_开发技巧rintf command for displaying values,but in salesforce which command we can use for displaying the data from the apex class.kindly let me know as soon as possible.

System.debug('some string'). See the apex language reference doc for more info.

Use System.debug('print content'); or you can also use in the controller: ApexPages.addMessage(new ApexPages.Message(ApexPages.Severity.ERROR, 'print content')); and in the actual page use: apex:messages /