atoi implementation in C

Algo for you own implementation of atoi :) :)

int val = 0;
   for each char in the string
      val = val *10 + char-48


lets write some code for it :)

int myatoi(char *convetIt)
{
     int val = 0;
     while(*convetIt)
     {
          val = (val * 10) + *convetIt - 48;
          convetIt++;
     }
}

So how it works? lets see how it works
take an example of string "123"

formula : val = (val * 10 ) + *convetIt - 48
                val = (0 * 10 ) + '1' - 48      =>      0*10  + 49 - 48 =  0  + 1 = 1
                val = (1 * 10)  + '2' - 48      =>     1*10  + 50 - 48 = 10  + 2 = 12
                val = (12 * 10 ) + '3' - 48    =>   12*10 + 51 - 48 = 120 + 3 = 123

so val contains 123 now :) . so how come '1' '2' '3' is replaced with 49,50,51 ? they are the asci values of these characters ,hence this logic.

There is some efficient way to implement this , lets see if anyone comes up with that method.

Remember it wont take care of the decimal values .