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C# String Concatenation

String concatenation is the process of combining two or more strings to form a single string. This can be done using the + operator, the String.Concat() method, or the StringBuilder class for efficient concatenation in loops.

Key Topics

1. Using the + Operator

Example: Concatenation with + Operator

string firstName = "John";
string lastName = "Doe";
string fullName = firstName + " " + lastName;
Console.WriteLine(fullName);  // Outputs: John Doe

2. Using String.Concat()

Example: Concatenation with String.Concat()

string part1 = "Hello";
string part2 = "World";
string message = String.Concat(part1, " ", part2);
Console.WriteLine(message);  // Outputs: Hello World

3. Using StringBuilder

The StringBuilder class is efficient for concatenating large numbers of strings, especially within loops.

Example: Concatenation with StringBuilder

using System.Text;

StringBuilder sb = new StringBuilder();
for(int i = 0; i < 5; i++)
{
    sb.Append("Number ");
    sb.Append(i);
    sb.Append("\n");
}
Console.WriteLine(sb.ToString());

Key Takeaways

  • Use + for simple concatenations.
  • String.Concat() can concatenate multiple strings efficiently.
  • StringBuilder is recommended for concatenations in loops.
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