Hi all, I have the following method where I manage various lists: "llistaAccions" is a list containing identificators to the actions that I need to execute sequentally until the previous to the last one. "llistaParamsColors", "llistaParamsRects", "llistaParamsDoubles" and "llistaParamsInts" contain the parameters of each action. Now, I use QMutableListIterators to iterate through the lists but I think that the code can be slighty more efficient because I go through the list sequentally and, also, I need to delete only the last items on each list and not the items in the middle. Here's the code:

Qt Code: 
  1. void MyApp::executeAllUntilPrevious()
  2. {
  3. 	int aux1, aux2, aux3, aux4;
  4. 	double auxd1, auxd2, auxd3, auxd4;
  5. 	QImage imatgeEnganxar;
  6.  
  7. 	llistaAccions.removeLast();
  8.  
  9. 	QMutableListIterator<IdentificadorAccions> itAccions(llistaAccions);
  10. 	QMutableListIterator<QColor> itColors(llistaParamsColors);
  11. 	QMutableListIterator<QRect> itRects(llistaParamsRects);
  12. 	QMutableListIterator<double> itDoubles(llistaParamsDoubles);
  13. 	QMutableListIterator<int> itInts(llistaParamsInts);
  14.  
  15. 	while(itAccions.hasNext())
  16. 	{
  17. 		switch(itAccions.next())
  18. 		{
  19. 		case Rotat:
  20. 			rotat(itColors.next(), itDoubles.next());
  21. 			break;
  22.  
  23. 		case Retallat:
  24. 			retallat(itRects.next());
  25. 			break;
  26.  
  27. 		case Pintat:
  28. 			pintat(itColors.next(), itRects.next());
  29. 			break;
  30.  
  31. 		case Copiat:
  32. 			if (itAccions.hasNext())
  33. 				imatgeEnganxar = foto -> copiarImatge(itRects.next());
  34. 			else
  35. 				itAccions.remove();
  36. 			break;
  37.  
  38. 		case Enganxat:
  39. 			enganxat(itRects.next(), imatgeEnganxar);
  40. 			break;
  41.  
  42. 		case Restaurat:
  43. 			restaurat();
  44. 			break;
  45.  
  46. 		case EscalatCm:
  47. 			auxd1 = itDoubles.next();
  48. 			auxd2 = itDoubles.next();
  49. 			canviTamanyCm(auxd1, auxd2);
  50. 			break;
  51.  
  52. 		case EscalatPixels:
  53. 			aux1 = itInts.next();
  54. 			aux2 = itInts.next();
  55. 			canviTamanyPixels(aux1, aux2);
  56. 			break;
  57.  
  58. 		case CanviatResolucioPixelsCm:
  59. 			aux1 = itInts.next();
  60. 			aux2 = itInts.next();
  61. 			canviResolucioPixelsCm(aux1, aux2);
  62. 			break;
  63.  
  64. 		case CanviatResolucioPixelsPolzada:
  65. 			aux1 = itInts.next();
  66. 			aux2 = itInts.next();
  67. 			canviResolucioPixelsPolzada(aux1, aux2);
  68. 			break;
  69.  
  70. 		case CanviatMargesCm:
  71. 			auxd1 = itDoubles.next();
  72. 			auxd2 = itDoubles.next();
  73. 			auxd3 = itDoubles.next();
  74. 			auxd4 = itDoubles.next();
  75. 			canviTamanyMargesCm(itColors.next(), auxd1, auxd2, auxd3, auxd4);
  76. 			break;
  77.  
  78. 		case CanviatMargesPixels:
  79. 			aux1 = itInts.next();
  80. 			aux2 = itInts.next();
  81. 			aux3 = itInts.next();
  82. 			aux4 = itInts.next();
  83. 			canviTamanyMargesPixels(itColors.next(), aux1, aux2, aux3, aux4);
  84. 		}
  85. 	}
  86.  
  87.         //This part is a bit "dirty" and I think that could be achieved with just one sentence...
  88. 	while(itColors.hasNext())
  89. 	{
  90. 		itColors.next();
  91. 		itColors.remove();
  92. 	}
  93.  
  94. 	while(itRects.hasNext())
  95. 	{
  96. 		itRects.next();
  97. 		itRects.remove();
  98. 	}
  99.  
  100. 	while(itDoubles.hasNext())
  101. 	{
  102. 		itDoubles.next();
  103. 		itDoubles.remove();
  104. 	}
  105.  
  106. 	while(itInts.hasNext())
  107. 	{
  108. 		itInts.next();
  109. 		itInts.remove();
  110. 	}
  111. }
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Well, I've readed that STL style iterators can be slightly faster than the Java-style iterators (QMutableListIterator). And, inside the STL style iterators, QList::const_iterator is slightly faster than QList::iterator. First of all, do you think that I really need iterators with the code above to obtain a better performance and/or readability? And, in that case, what kind of iterator you think that could fit better in what I need to do: iterate sequentially through the lists and, at the end, delete all the items from the current position until the end. Thanks.