lex n yacc

[sruthimjs]

Hey! am totally new to ubuntu..tried installing lex by using
sudo aptitude install flex

Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initialising package states... Done
Building tag database... Done
No candidate version found for flex
No candidate version found for flex
No packages will be installed, upgraded, or removed.
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0B of archives. After unpacking 0B will be used.
Writing extended state information... Done
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initialising package states... Done
Building tag database... Done
any idea why the packages aren't being installed?

[Partyboi2]

Hi, check under Software Sources (System>Admin>Software Sources) that you have on the the first tab all the repos except source code selected and reload the package list. Another thing you could also try as well is to change your download server under Software Sources on the first tab.