Write methods and use collections
Create reusable methods and process growable lists of values.
- Define methods with return values and use List<T> with foreach.
A method names a reusable unit of behavior and can accept parameters and return a value. C# passes int values by value by default, so a method receives a copy. List<T> is a growable standard collection; Add appends values and foreach visits each item. Prefer collection APIs to manually managing memory for ordinary application code.
1using System;
2using System.Collections.Generic;
3
4class Program
5{
6 static int Sum(List<int> values)
7 {
8 int total = 0;
9 foreach (int value in values) total += value;
10 return total;
11 }
12}Sum returns the total of all list elements.
A method signature communicates its input and output types. Generics such as List<int> preserve the element type and let the compiler reject incompatible values before execution.
Key takeaways
Methods communicate behavior through parameters and return types.
List<T> grows as values are added.
foreach is clear when processing each element.
Lesson quiz
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