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how to save big number into array

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Re: how to save big number into array

#11

Dec 28th, 2008

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
int char2int(char c) {
   switch(c) {
      case '0': {
         return 0;
      }
      case '1': {
         return 1;
      }
      case '2': {
         return 2;
      }
      case '3': {
         return 3;
      }
      case '4': {
         return 4;
      }
      case '5': {
         return 5;
      }
      case '6': {
         return 6;
      }
      case '7': {
         return 7;
      }
      case '8': {
         return 8;
      }
      case '9': {
         return 9;
      }
   }
}
int char2int(char c) {
   switch(c) {
      case '0': {
         return 0;
      }
      case '1': {
         return 1;
      }
      case '2': {
         return 2;
      }
      case '3': {
         return 3;
      }
      case '4': {
         return 4;
      }
      case '5': {
         return 5;
      }
      case '6': {
         return 6;
      }
      case '7': {
         return 7;
      }
      case '8': {
         return 8;
      }
      case '9': {
         return 9;
      }
   }
}

Take advantage of the fact that '0' through '9' are contiguous on the ASCII chart and that you can subtract characters.

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
int char2int(char c)
{
     if (c < 48 || c > 57)
          return -1;  // signifies non-digit/invalid
 
     return c - 48;  // '0' is 48 in ASCII
}
int char2int(char c)
{
     if (c < 48 || c > 57)
          return -1;  // signifies non-digit/invalid

     return c - 48;  // '0' is 48 in ASCII
}