public static string GetRandomStringWithoutSpaces(int length, FastRandom rand) {
   StringBuilder strBuilder = new StringBuilder(length);
   for (int i = 0; i < length; i++) {
     strBuilder.Append(GetRandomCharWithoutSpace(rand));
   }
   return strBuilder.ToString();
 }
 public static char GetRandomCharWithoutSpace(FastRandom rand) {
   int value = rand.Next(0, 95);
   switch (value) {
     case 0:
       return '\t';
     case 1:
       return '\n';
     default:
       return (char)(value + 31);
   }
 }
 private static char GetRandomChar(FastRandom rand) {
   int value = rand.Next(0, 96);
   switch (value) {
     case 0:
       return '\t';
     case 1:
       return '\n';
     default:
       return (char)(value + 30);
   }
 }
 private static char GetRandomPrintableCharExceptUpperCase(FastRandom rand) {
   int value = rand.Next(0, 68) + 32;
   if (value < 65) return (char)value;
   return (char)(value + 26);
 }
 public static string GetRandomStringWithOnlyPrintableCharactersWithoutUpperCaseCharacters(int length, FastRandom rand) {
   StringBuilder strBuilder = new StringBuilder(length);
   for (int i = 0; i < length; i++) {
     strBuilder.Append(GetRandomPrintableCharExceptUpperCase(rand));
   }
   return strBuilder.ToString();
 }
 public static IEnumerable<string> GetRandomStringsWithoutSpaces(int n, int minLength, int maxLength, FastRandom rand) {
   for (int i = 0; i < n; i++) {
     yield return StringValueGenerator.GetRandomStringWithoutSpaces(rand.Next(minLength, maxLength), rand);
   }
 }
 private static char GetRandomLowerCaseChar(FastRandom rand) {
   int value = rand.Next(0, 25);
   return (char)(value + 97);
 }
 public static string GetRandomLowerCaseString(int length, FastRandom rand) {
   StringBuilder strBuilder = new StringBuilder(length);
   for (int i = 0; i < length; i++) {
     strBuilder.Append(GetRandomLowerCaseChar(rand));
   }
   return strBuilder.ToString();
 }