Plagiarism is using others' ideas and words without clearly acknowledging the source of that information.
Although plagiarism is commonly thought of as using a direct quote without citing the source, there are other types of plagiarism, too.
Piecing together sentences, using key words from someone else or just using someone else's ideas without citing the source can be considered plagiarism.
Some universities also consider a student using the same paper for more than one class to be plagiarism because original work isn't being done for each class.
A charge of plagiarism can have severe consequences. Oregon Tech defines plagiarism as "submitting the language, ideas, thoughts or work of another as ones own or assisting in the act of plagiarism by allowing ones work to be used in this fashion." For the Oregon Tech policy on academic dishonesty, including plagiarism, see the Student Policies & Procedures available online at the link below.
To avoid plagiarism, you must give credit whenever you use:
It is also considered plagiarism if you take program code written by another person and present it as your own work.
Almost all computer programs contain many ideas borrowed from elsewhere. Many also contain short sections of actual code copied from elsewhere. For example, writing a section of program to create a new window on screen with a menu at the top of the window is often done by simply copying a few of lines of code from an example in a programming manual or textbook, either with or without a few minor changes. This is normally regarded as fair use and typically requires no acknowledgment.
Any more significant copying of code from elsewhere should be acknowledged, however. The acknowledgment can be put in comments within the program itself. Obviously, it is not possible to put sections of code in quotation marks to indicate that they have been taken directly from elsewhere. Instead, the comments should make it clear which sections of code have been copied from elsewhere. Equally, the comments should make it clear when the basic method has been copied from elsewhere, but changes made to the details.