public static bool TestTo7(string accountNumber, int index)
{
string falseAccountNumber = accountNumber;
falseAccountNumber = falseAccountNumber.Remove(index, 1).Insert(index, "7").Remove(9);
return(NumberFinder.CheckIfAccountIsValid(falseAccountNumber));
}
public static bool TestTo9(string accountNumber, int index)
{
string falseAccountNumber = accountNumber;
falseAccountNumber = falseAccountNumber.Remove(index, 1).Insert(index, "9");
if (falseAccountNumber.Length > 9)
{
falseAccountNumber = falseAccountNumber.Remove(9);
}
return(NumberFinder.CheckIfAccountIsValid(falseAccountNumber));
}
public static bool TestTheTwoCasesOf9(string accountNumber, int index)
{
bool isPossible9 = false;
string falseAccountNumber = accountNumber;
falseAccountNumber = falseAccountNumber.Remove(index, 1).Insert(index, "5").Remove(9);
isPossible9 = NumberFinder.CheckIfAccountIsValid(falseAccountNumber);
if (!isPossible9)
{
isPossible9 = TestTo8(falseAccountNumber, index);
}
return(isPossible9);
}
public static bool TestAllNumbers(string accountNumber, int index)
{
bool isPossible = false;
string falseAccountNumber = accountNumber.Remove(9);
for (int j = 0; j < 10; j++)
{
falseAccountNumber = falseAccountNumber.Remove(index, 1).Insert(index, j.ToString());
isPossible = NumberFinder.CheckIfAccountIsValid(falseAccountNumber);
if (isPossible)
{
return(true);
}
}
return(false);
}