Test automation is something which is under taken as a test 
approach when a project requires a continuous or repetitive 
testing approach, which obviously depends on the project 
involved. But manual testing can be handled in places where 
we cannot automate or difficult to automate. So, the thing 
is both manual and automation cannot be compared as better 
than the other. It depends on the objective or project that 
we are going to take up manual or automation.

Like chithra said, we cannot compare them. Every method has 
its advantages and disadvantages. But manual testing is the 
mandatory, We can proceed to automation only after the 
manual testing. Automation testing is mainly used for 
repetative testing and for the large applications. Manual 
testing is mandatory and effective way of testing but it 
takes time and human resource.

we can say automation is better if can have some hands in C 
language . because manual is compulsory in any kind of 
appication after finishing smoke test in manual or testing 
the application manually we will be starting preparation of 
automation scripts. so knowing automation tools will pay us 
more then having only manual.