You’ve tagged this as C++ as well as C. If you’re using C++ things are a lot easier. The standard template library has a template called vector which allows you to dynamically build up a list of objects. If you’re using C things are a lot harder, yes malloc, realloc and free are the tools … Read more
Actually, the two first ideas pass the array by address and the third passes the array by reference. You can devise a little test to check this: The output of this test is If a parameter is passed by value, it cannot be modified inside a function because the modifications will stay in the scope of the function. In … Read more
I don’t believe MySQL supports dynamic sql. You can do “prepared” statements which is similar, but different. Here is an example: The prepared statements are often used to see an execution plan for a given query. Since they are executed with the execute command and the sql can be assigned to a variable you can approximate the some of … Read more
There are several flavors of arrays, depending on how and where they are declared. Fixed-length Arrays Fixed-length arrays must have their size determined at compile time. You cannot change the size of a fixed-length array after it has been defined. Fixed-length arrays are declared in one of the following ways: In the first three cases, … Read more
You meant to type: And you also need to delete[] collection (or you’ll leak this memory). It would be better use std::vector<std::string> collection; and avoid the raw pointer usage altogether:
For C++: If you just need a container just use std:vector. It will take care all the memory allocations necessary for you. However if you want to develop your own dynamic container (whatever reasons you have) you have to take care off the memory allocations yourself. That is, when your array grows you have to allocate new … Read more
Local arrays are created on the stack, and have automatic storage duration — you don’t need to manually manage memory, but they get destroyed when the function they’re in ends. They necessarily have a fixed size: Arrays created with operator new[] have dynamic storage duration and are stored on the heap (technically the “free store”). They can … Read more
The difference is that apply lets you invoke the function with arguments as an array; call requires the parameters be listed explicitly. A useful mnemonic is “A for array and C for comma.” See MDN’s documentation on apply and call. Pseudo syntax: theFunction.apply(valueForThis, arrayOfArgs) theFunction.call(valueForThis, arg1, arg2, …) There is also, as of ES6, the possibility to spread the array for use with the call function, you can see the compatibilities here. Sample code: