C# Fundamentals

Declare variables with explicit types and with var, and know when each reads better.

Choose between const and readonly for values that must not change.

Pick the right numeric type and understand overflow and precision limits.

Build, compare and format text, and avoid the cost of repeated concatenation.

Convert between types safely using casts, Convert and TryParse.

Apply arithmetic, comparison, logical and null-coalescing operators with correct precedence.

Branch clearly, including with the conditional operator where it aids readability.

Replace long condition chains with a switch, and use switch expressions for value selection.

Use for, foreach, while and do-while, and control flow with break and continue.