Say you’re building checkout for an Austin outdoor-gear store. It takes credit cards today, ACH bank debits next month and gift cards by the holidays, and the checkout code shouldn’t change each time. Quick answer: abstraction in C# means exposing what an object does, like Pay(amount), and hiding how it does it behind an abstract … Read more >>

If you need to compare two strings character by character in C#, loop over the indexes up to the shorter length with Math.Min, return the first index where a[i] != b[i], and count a leftover tail as a difference. For a plain yes or no, or the length of the matching start, span methods like … Read more >>

Imagine a recruiter from a Dallas insurance company books your first .NET phone screen for Monday: 30 minutes, “mostly C# basics.” You’ve got one weekend. Most C# interview questions for freshers come from six areas: types, OOP, strings and collections, exceptions, LINQ and async basics, and modern C# features. Quick answer: learn the 40 questions … Read more >>

The first thing most people type to sort an array in C# is var sorted = Array.Sort(prices);, and the compiler stops right there: Array.Sort sorts the array you pass in place and returns void, so call it on its own line and keep using prices. We’ll build a state population ranking on .NET 10, one … Read more >>

To remove a character from a string in C#, call Replace with the character as a string and an empty string as the replacement. It deletes every occurrence in one line: Need only the first or last match instead? That’s Remove plus IndexOf. I ran each method below on .NET 10 with US phone numbers, … Read more >>

A Phoenix freight client sent me an order import that crashed on row 7 because a dispatcher typed “N/A” in the quantity column. One bad cell killed the whole nightly run. In this tutorial, I’ll cover try catch in C# on .NET 10: the syntax, catching specific exceptions in the right order, finally, exception filters, … Read more >>

Blank customer names kept slipping into a Dallas client’s CRM import because my code only tested for null. For a C# check if string is null or empty, call string.IsNullOrEmpty(value). If spaces should count as empty too, use string.IsNullOrWhiteSpace(value). In this tutorial, I’ll go through the C# check if string is null or empty options … Read more >>

Last spring, a sales dashboard I was building for a US retail client crashed on one innocent line: regions[4]. The array held four regions, and index 4 simply doesn’t exist. Here’s the quick answer. A C# array is a fixed-size, zero-indexed block of values of one type, such as string[] regions = [“West”, “South”];. You … Read more >>

Last spring, an order import for a Texas retailer crashed because the Quantity column came back empty on a few rows. To do a C# convert null to int, keep the value in an int? and pick a fallback with ??: In this tutorial, I’ll show every C# convert null to int option I use … Read more >>

If you’ve written a Fee() method in a C# derived class and called it through a base-class variable, you’ve probably watched the base version run anyway, with a CS0108 warning in the build output. That’s because method overriding in C# takes two keywords: virtual on the base method and override on the derived one. Leave … Read more >>