108 lines
2.4 KiB
Markdown
108 lines
2.4 KiB
Markdown
---
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title: "Полезности"
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categories: ["cpp", "archive"]
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date: 2015-12-01T00:00:00+03:00
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draft: false
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featured_image: miniature.jpg
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---
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На этой страничке я собираю все полезные кусочки кодов, которые мне пригождаются.
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<!--more-->
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# С/С++:
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## Вывод списка файлов в папке, dirent:
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```c
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DIR *dir;
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struct dirent *ent;
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if (dir = opendir ("mydir")) {
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while (ent = readdir (dir)) {
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printf ("%s\n", ent->d_name);
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}
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closedir (dir);
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}
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```
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## Удаление элементов вектора во время итерации:
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```cpp
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vector< string >::iterator it = curFiles.begin();
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while(it != curFiles.end()) {
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if(something) {
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it = curFiles.erase(it);
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} else ++it;
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}
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```
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## Освобождение памяти вектора:
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```cpp
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struct delete_ptr {
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template <typename P>
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void operator () (P p) {
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delete p;
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}
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};
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std::for_each(myvector.begin(), myvector.end(), delete_ptr());
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myvector.clear();
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```
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## Построковое чтение файла:
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```c
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const char filename[] = "file.txt";
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FILE *file = fopen(filename, "r");
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if (file != NULL) {
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char line[128];
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while (fgets(line, sizeof line, file) != NULL)
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{
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fputs(line, stdout);
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}
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fclose(file);
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}
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```
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## OpenGL, рисование цветных прямоугольников:
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```cpp
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void drawRect(int x1, int y1, int x2, int y2, int color) {
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float alpha = (float) (color >> 24 & 255) / 255.0F;
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float red = (float) (color >> 16 & 255) / 255.0F;
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float green = (float) (color >> 8 & 255) / 255.0F;
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float blue = (float) (color & 255) / 255.0F;
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glColor4f(red, green, blue, alpha);
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glBegin(GL_QUADS);
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glVertex3f(x1, y2, 0.0F);
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glVertex3f(x2, y2, 0.0F);
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glVertex3f(x2, y1, 0.0F);
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glVertex3f(x1, y1, 0.0F);
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glEnd();
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}
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void drawRectAt(int x, int y, int width, int height, int color) {
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drawRect(x, y, x + width, x + height, color);
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}
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void drawPixel(int x, int y, int color) {
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drawRect(x, y, x + 1, y + 1, color);
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}
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```
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## Количество дней в месяце (с учётом високостного года):
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```c
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int get_month_days(int year, int month){
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if (month == 4 || month == 6 || month == 9 || month == 11){
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return 30;
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} else if (month == 2) {
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return ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0)) ? 29 : 28;
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} else return 31;
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}
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```
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