Task: Bulls and cows

C: #include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdbool.h>
#include <curses.h>
#include <string.h>

#define MAX_NUM_TRIES 72
#define LINE_BEGIN 7
#define LAST_LINE 18

int yp=LINE_BEGIN, xp=0;

char number[5];
char guess[5];

#define MAX_STR 256
void mvaddstrf(int y, int x, const char *fmt, ...)
{
  va_list args;
  char buf[MAX_STR];
  
  va_start(args, fmt);
  vsprintf(buf, fmt, args);
  move(y, x);
  clrtoeol();
  addstr(buf);
  va_end(args);
}

void ask_for_a_number()
{
  int i=0;
  char symbols[] = "123456789";

  move(5,0); clrtoeol();
  addstr("Enter four digits: ");
  while(i<4) {
    int c = getch();
    if ( (c >= '1') && (c <= '9') && (symbols[c-'1']!=0) ) {
      addch(c);
      symbols[c-'1'] = 0;
      guess[i++] = c;
    }
  }
}

void choose_the_number()
{
  int i=0, j;
  char symbols[] = "123456789";

  while(i<4) {
    j = rand() % 9;
    if ( symbols[j] != 0 ) {
      number[i++] = symbols[j];
      symbols[j] = 0;
    }
  }
}








VB: Option Explicit

Sub Main_Bulls_and_cows()
Dim strNumber As String, strInput As String, strMsg As String, strTemp As String
Dim boolEnd As Boolean
Dim lngCpt As Long
Dim i As Byte, bytCow As Byte, bytBull As Byte
Const NUMBER_OF_DIGITS As Byte = 4
Const MAX_LOOPS As Byte = 25 

    strNumber = Create_Number(NUMBER_OF_DIGITS)
    Do
        bytBull = 0: bytCow = 0: lngCpt = lngCpt + 1
        If lngCpt > MAX_LOOPS Then strMsg = "Max of loops... Sorry you loose!": Exit Do
        strInput = AskToUser(NUMBER_OF_DIGITS)
        If strInput = "Exit Game" Then strMsg = "User abort": Exit Do
        For i = 1 To Len(strNumber)
            If Mid(strNumber, i, 1) = Mid(strInput, i, 1) Then
                bytBull = bytBull + 1
            ElseIf InStr(strNumber, Mid(strInput, i, 1)) > 0 Then
                bytCow = bytCow + 1
            End If
        Next i
        If bytBull = Len(strNumber) Then
            boolEnd = True: strMsg = "You win in " & lngCpt & " loops!"
        Else
            strTemp = strTemp & vbCrLf & "With : " & strInput & " ,you have : " & bytBull & " bulls," & bytCow & " cows."
            MsgBox strTemp
        End If
    Loop While Not boolEnd
    MsgBox strMsg
End Sub

Function Create_Number(NbDigits As Byte) As String
Dim myColl As New Collection
Dim strTemp As String
Dim bytAlea As Byte

    Randomize
    Do
        bytAlea = Int((Rnd * 9) + 1)
        On Error Resume Next
        myColl.Add CStr(bytAlea), CStr(bytAlea)
        If Err <> 0 Then
            On Error GoTo 0
        Else
            strTemp = strTemp & CStr(bytAlea)
        End If
    Loop While Len(strTemp) < NbDigits
    Create_Number = strTemp
End Function

Function AskToUser(NbDigits As Byte) As String
Dim boolGood As Boolean, strIn As String, i As Byte, NbDiff As Byte

    Do While Not boolGood
        strIn = InputBox("Enter your number (" & NbDigits & " digits)", "Number")
        If StrPtr(strIn) = 0 Then strIn = "Exit Game": Exit Do
        If strIn <> "" Then
            If Len(strIn) = NbDigits Then
                NbDiff = 0
                For i = 1 To Len(strIn)
                    If Len(Replace(strIn, Mid(strIn, i, 1), "")) < NbDigits - 1 Then
                        NbDiff = 1
                        Exit For
                    End If
                Next i
                If NbDiff = 0 Then boolGood = True
            End If
        End If
    Loop
    AskToUser = strIn
End Function