daydayup questions

• confusion of char *notes[] = {"Ab", "F#", "B", "Gb", "D"}; and char**
• How to intuitively understand larger than/less than operator in comparator of C++ priority queue container
• how to correctly use ctime() to print different time stamps
• How to compute the union polygon of two (or more) rectangles
• Shape_area and ALAND AWATER in Tiger census data
• opengl glLineWidth() doesn't change size of lines
• Presto array contains an element that likes some pattern
• c++ regex extract all substrings using regex_search()
• How can I use a C++ unordered_set for a custom class?

daydayup answers