What does the question mark character (‘?’) mean in C++?

This is commonly referred to as the conditional operator, and when used like this: … if the condition evaluates to true, the expression evaluates to result_if_true, otherwise it evaluates to result_if_false. It is syntactic sugar, and in this case, it can be replaced with Note: Some people refer to ?: it as “the ternary operator“, because it is the only ternary operator (i.e. operator that … Read more

Why do I have to “git push –set-upstream origin “?

TL;DR: git branch –set-upstream-to origin/solaris The answer to the question you asked—which I’ll rephrase a bit as “do I have to set an upstream”—is: no, you don’t have to set an upstream at all. If you do not have upstream for the current branch, however, Git changes its behavior on git push, and on other commands as well. The … Read more

Java optional parameters

There are several ways to simulate optional parameters in Java: Method overloading.void foo(String a, Integer b) { //… }void foo(String a) { foo(a, 0); // here, 0 is a default value for b }foo(“a”, 2); foo(“a”); One of the limitations of this approach is that it doesn’t work if you have two optional parameters of … Read more

C++ Linked List Node with class

Specifically, the goal here is to create a linked structure that has some number of nodes, between 5 and 2 million. Don’t worry that this number is large or that values may wrap around past the max size of integer. If you have created your linked structure correctly, a modern computer can breeze through this … Read more

How to mkdir only if a directory does not already exist?

Try mkdir -p: Note that this will also create any intermediate directories that don’t exist; for instance, will create directories foo, foo/bar, and foo/bar/baz if they don’t exist. Some implementation like GNU mkdir include mkdir –parents as a more readable alias, but this is not specified in POSIX/Single Unix Specification and not available on many common platforms like macOS, various BSDs, and various commercial … Read more

How to compare files from two different branches

git diff can show you the difference between two commits: Or, equivalently: Note you must specify the relative path to the file. So if the file were in the src directory, you’d say src/myfile.cs instead of myfile.cs. Using the latter syntax, if either side is HEAD it may be omitted (e.g., master.. compares master to HEAD). You may also be interested in mybranch…master (from git diff documentation): This form is … Read more

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