Detecting plagiarism in computer source code

A non-transitory computer-readable storage medium storing executable instructions to cause a computer system to perform a method comprising:

• creating a first array of lines of functional program code from a first program source code file, the first program source code file including the lines of functional program code of a first program and lines of non-functional comments of the first program;
• creating a second array of lines of non-functional comments from a second program source code file, the second program source code file including lines of functional program code of a second program and lines of non-functional comments of the second program, wherein the second array of non-functional comments is created using a predefined list of special characters to determine the beginning and end of comments in the second program source code file;
• calculating a code-to-comment similarity number based on performing a comparison of the lines of functional program code from the first array with the lines of non-functional comments from the second array to find instances of similarity, wherein calculating the code-to-comment similarity number comprises finding a number of matching functional program code statements in the first array and non-functional comments in the second array indicating that the non-functional comments of the second program source code file contain functional program code of the first program source code file;
• and
• presenting to a user an indication of disguised copying of the first program source code file wherein said indication of disguised copying is defined by the similarity number.

A computer-implemented apparatus comprising:

• a computer;
• and
• a source code matching program on the computer, wherein execution of the source code matching program causes the computer to perform a method comprising:
• creating a first array of lines of functional program code from a first program source code file, the first program source code file including the lines of functional program code of a first program and lines of non-functional comments of the first program;
• creating a second array of lines of non-functional comments from a second program source code file, the second program source code file including lines of functional program code of a second program and lines of non-functional comments of the second program, and wherein the second array of non-functional comments is created using a predefined list of special characters to determine the beginning and end of comments in the second program source code file;
• calculating a code-to-comment similarity number based on performing a comparison of the lines of functional program code from the first array with the lines of non-functional comments from the second array to find instances of similarity, wherein calculating the code-to-comment similarity number comprises finding a number of matching functional program code statements in the first array and non-functional comments in the second array indicating that the non-functional comments of the second program source code file contain functional program code of the first program source code file;
• and
• presenting to a user an indication of disguised copying of the first program source code file wherein said indication of disguised copying is defined by the similarity number.