runtime error,debugger stops at "int y" line 147, i need a hint

[dark219]

nvm i got it

The program runs ok if i put valid inputs, but when i input 123 for binary this will happen:

Input binary #: 123

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

the debugger is ok until at "int y" at line 147, thats when the console will exit
i used bloodshed dev c++ and windows 7...
can someone give me a hint what went wrong?

#include <iostream>
#include <iomanip>
#include <sstream>
#include <bitset>

using namespace std;

// converts dec to bin and prints it in reverse        
int dectobin(int x)
{

    cout<<"The binary equivalent is:";
    stringstream buff;
      do
      {
      buff<<x%2;
      x=x/2; 
      }while (x>=2);
      if(x>0)
      {
      buff<<'1';
      }
      string cool=buff.str();
      buff.str("");
      buff.clear();
      int i=cool.length();
      for (i;i>=0;i--)
      {
      cout <<cool[i];
      } 
      cout<<endl;
      return 0;
}

//input validation function
int validate(char check)
{
string number;
int ok;
           
switch(check)
{

         //case c if hex input
         case 'C': case 'c':
         {
         do
         {
         ok =1;
         cin >>setw(1000)>> number;

         for (int i=0;i<number.length();i++)
         {
         if (isxdigit(number[i]))
         continue;
         
         else
         {
         cerr<<"Invalid input, try again\n";
         ok=0; 
         break;
         }    
         }
         }while (ok==0);
         
         //returns hex value in dec
         stringstream x;
         x<<hex<<number;
         int y;
         x>>y;
         x.str("");
         x.clear();
         return y;
         break;
         }
         
         //dec oct bin base type input
         default:

         do
         {
         ok =1;
         cin >>setw(1000)>> number;

         for (int i=0;i<number.length();i++)
         {
         
         //a for dec, numbers only    
         if (isdigit(number[i]))
         {
         if (check =='a' || check=='A')
         {
         continue;
         }
         
         //converts number[i] to int
         stringstream buffer;
         buffer<<number[i];
         int compare;
         buffer>>compare;
         buffer.str("");
         buffer.clear();
         
         //b for oct, <8 only
         if (compare<8)
         {
         if (check =='b' || check=='B')
         {
         continue;
         }
         }
         
         //d for bin, <2 only
         if (compare<2)
         {
         if (check =='d' || check=='D')
         {
         continue;
         }
         }
         }
         
         else
         {
         ok =0;
         cerr<<"Invalid input, try again\n";
         break;
         }
         }
        }while (ok==0);     
}

// converts number and returns it
stringstream x;
if(check=='a'||check=='A')
{
x<<number;
}
else if(check=='b'||check=='B')
{
x<<oct<<number;
}
else if(check=='d'||check=='D')
{
x<<bitset<32>(number).to_ulong();
}
int y;
x>>y;
x.str("");
x.clear();
return y;
}              

//conversion function
int convert(int x)
{
    cout<<"Convert to:\nA: for decimal\nB: for octal\nC: for hexadecimal\nD: for binary\n";
    char select;
    cin>>setw(2)>>select;
    stringstream buff;
    buff<<dec<<x;
    int z;
    buff>>z;
    buff.str("");
    buff.clear();
    
    
    switch(select)
{
    case 'a':
         case 'A':
         cout<<"The decimal equivalent is: "<<dec<<z<<endl;
         break;
    case 'b':
         case 'B':
         cout<<"The octal equivalent is: "<<oct<<z<<endl;
         break;
    case 'c':
         case 'C':
         cout<<"The hexadecimal equivalent is: "<<hex<<z<<endl;
         break;
    case ('d'):
         case ('D'):
         dectobin(z);
         break;
    default:
         cout<<"Invalid input\n";
         break;
}
         return 0;
}


int main()
{
char again='y'; 

do
{    
cout<<"Choose input type:\nA: for decimal\nB: for octal\nC: for hexadecimal\nD: for binary\n";
char select;
cin>>setw(2)>>select;

switch(select)
{
    case 'a':
         case 'A':
              
    cout<<"Input decimal #: \n";
    convert(validate(select));
    break;
    
    case 'b':
         case 'B':
    cout<<"Input octal #: 0";
    convert(validate(select));
    break;
    
    case 'c':
         case 'C':
    cout<<"Input hexadecimal #: 0x";
    convert(validate(select));
    break;
    
    case 'd':
         case 'D':
    cout<<"Input binary #: ";
    convert(validate(select));
    break;
         
    default:
         cerr<<"Invalid input\n";
         system("pause");
         break;

}
cout<<"Enter Y to try again:";
cin>>again;
system("cls"); 
}while ((again=='y')||(again=='Y'));

system("pause");
return 0;

}