An alternative to the StringBuilder
approach:
static class StringExt
{
public static string InsertAfterEvery(
this string source, string insert, int every, string find)
{
int numberFound = 0;
int index = 0;
while (index < source.Length && index > -1)
{
index = source.IndexOf(find, index) + find.Length;
numberFound++;
if (numberFound % every == 0)
{
source = source.Insert(index, insert);
index += insert.Length;
}
}
return source;
}
}
// I used 3 rather than 15
Console.WriteLine(
"db 4Dh, 5Ah, 80h, 00h, 01h, 00h, 00h, 00h, 04h,".InsertAfterEvery(
Environment.NewLine, 3, ","));
solved How to add a char every X specific char in C# [closed]