File 1                                  File 2                       
1 /* ---- begin routine ---- */         1 /* find the file extension */ 
2 void fdiv(                            2 void file_divide(             
3   char *fname, // file name           3 char      *fname,             
4   char *path)   /* path */            4 char      *path)              
5 {                                     5 {                             
6   int Index1, j;                      6   int i, j;                    
7                                       7   while (1)     // loop here  
8   while (1)                           8     j = strlen(fname);         
9       j = strlen(fname);              9                               
10 // find the file extension           10                               

File 1                                  File 2            
3     char *fname, // file name         3 char      *fname,    
4     char *path)   /* path */          4 char      *path)     
9        j = strlen(fname);             8    j = strlen(fname);

Figure 3: Source Line Matching. (a) Two files; (b) matching source lines in File 1 and File 2.