According to the TIOBE index, the C programming language is the most popular language in April 2010.
The TIOBE Programming Community index gives an indication of the popularity of programming languages. The index is updated once a month. The ratings are based on the number of skilled engineers world-wide, courses and third party vendors. The popular search engines Google, MSN, Yahoo!, Wikipedia and YouTube are used to calculate the ratings. The TIOBE index does not show the best programming language or the language in which most lines of code have been written.