Can somebody please tell me that what is SingleEmailMessage in "Messaging.SingleEmailMessage".
I have uderstood that Messaging is a class but I haven't understood what is SingleEmailMessage. Is it a static method or innerclass or what?

I have to take any standard or custom object. Apply approval process on it  and approve the pending records which are pending from last two days through an apex schedulable class that should run once after every 24 hours.
For which i have to write a code.
Please help.

Can somebody please tell me that what is SingleEmailMessage in "Messaging.SingleEmailMessage".
I have uderstood that Messaging is a class but I haven't understood what is SingleEmailMessage. Is it a static method or innerclass or what?