how to color certain words in a textedit

[chandrabose.s]

hi
i'm using qt3.0.i have to color certain strings/keywords in a textedit while opening the file as well as adding characters in a newly opened file which is similar to qteditor environment.
And also i have to parse the file for the words which should match the predefined words.
for eg.: ScanIn,ScanOut
i have to color the above two words and also check for predefined words,if it is not in the list i have to give an error message.
Please help me,its very urgent.
Give some example coding to do the task.
thanks in advance,
bose.