I want to get latitude and longitude of a city by providing the API with the city name. It should work for most cities regardless how the user inputs the city.
For examp
You can use Google's geocoding service, e.g.,
http://maps.googleapis.com/maps/api/geocode/xml?address=Miami+FL&sensor=false
That gives you back georeferenced data in a variety of formats (JSON, XML, etc). In any event, the location is definitely in the returned data block.
The API docs are at:
https://developers.google.com/maps/documentation/geocoding/