public static string addString(string src, string addStr) {
public static string removeLine(string src, int numRemove)
for(int loop=0; loop < numRemove; loop++) {
int pos = work.IndexOf('\n');
work = work.Substring(pos+1);
public static string addToRingBuffer(string src, string addStr, int maxline)
string work = src + addStr;
int numline = work.Count( c => c == '\n') + 1;
int numRemove = numline - maxline;
work = removeLine(work, numRemove);
public static void Main()
string text = "AAA\nBBB\nCCC\nDDD\nEEE\n";
text = addToRingBuffer(text, "FFF\n", 5);
text = addToRingBuffer(text, "GGG\n", 5);