java - Error when iterating arraylist with points of lines to check for intersection -


i'm developing code check intersection between lines. have points of lines stored in arraylist , below have code iterati throw arraylist compare 2 lines @ time. error message line: line line2 = new line(points.get(j), points.get(j+1)); it's j+1 causes error. if have j it's no problem, don't next point!? can't or have been thinking wrong in way? preciated locate error or suggestion alternative solution.

    // intersection control     if(touchactionup) {          (int = 0; < points.size()-3; i++) {             line line1 = new line(points.get(i), points.get(i+1));              (int j = + 2; j < points.size(); j++) {                 line line2 = new line(points.get(j), points.get(j+1));                  // call method check intersection                 if(checkintersection(line1, line2)) {                  }             }         }     }

yes, problem:

for (int j = + 2; j < points.size(); j++) {     line line2 = new line(points.get(j), points.get(j+1));

that keep incrementing until and including j = points.size() - 1 @ point calling points.get(j+1) calling points.get(points.size()) invalid index.

you want smaller lower bound:

for (int j = + 2; j < points.size() - 1; j++) {

it looks me you're not using list of points correctly though - if you're trying use pairs of points in list, i++ , j++ should i += 2 , j += 2 - otherwise you're going create lines points indexes of (0, 1), (1, 2), (2, 3) etc. maybe that's intention - if these meant lines describing single shape, example... if it's not, i'd encourage create list<line> instead, each line has pair of points. simpler work with.


Comments

Post a Comment

Popular posts from this blog

linux - Does gcc have any options to add version info in ELF binary file? -

i mean whether gcc can insert source code version infor elf binary section or similar. not want change source file, add info gcc option in makefile. you can emit version info text file, turn text file object file statically link executable. the first step simple have write code: script or write version info in format plain text file. write makefile rule produce version.o version.txt, using objcopy . you'll have object file 2 useful symbols defined in it: beginning , end of textual version info. add generated object executable, , you'll able access version 2 ways: running strings on binary, or writing code in application print version string (you'll need declare start , end symbols variables in header file).
Read more

java - Are there any classes that implement javax.persistence.Parameter<T>? -

i'm using named queries fetch entities database using jpa , hibernate , came across puzzling me: how come there no default implementations of javax.persistence.parameter interface? i rather impressed how @staticmetamodel used criteriabuilder in jpa2 meaning type safety , don't have mess around setting string names. wanted apply similar of jpa1 ejb's i'm working on: dealergroup_.class: public dealergroup_ { public parameter<integer> id = new parameterimpl<integer>("id"); /// etc... } dealergroupfacade.class: // ... public dealergroup fetch(integer id) { typedquery<dealergroup> query = em.createnamedquery("dealergroup.fetchbyid", dealergroup.class); query.setparameter(dealergroup_.id, query); return query.getsingleresult(); } // ... i surprised find there no implementations of parameter interface - of course, implement myself absence makes me suspicious may mistake using in way? should implementing parameter...
Read more

android - send complex objects as post php java -

is possible send contact numbers via post php class inside eclipse ? or post limited primitive types , have find work arounds send them string ? i propose: send them json in post request, befor start, have @ gson project , keep in mind set content application -> json. luck
Read more