fork download
copy 
  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4. void doubleDecimal(char * decimal)
  5. {
  6.     char buffer[256] = "";
  7.     char c;
  8.     unsigned char d, carry = 0;
  9.     int i = 0;
  10.  
  11.     while (c = decimal[i])
  12.     {
  13.         d = 2 * (c - '0') + carry;
  14.         buffer[i] = (d % 10) + '0';
  15.         carry = d / 10;
  16.         i++;
  17.     }
  18.  
  19.     if (carry > 0)
  20.         buffer[i++] = (carry % 10) + '0';
  21.  
  22.     buffer[i] = '\0';
  23.     strncpy(decimal, buffer, 256);
  24. }
  25.  
  26. void reverse(char * str)
  27. {
  28.     int i = 0;
  29.     int j = strlen(str) - 1;
  30.  
  31.     while (j > i)
  32.     {
  33.         char tmp = str[i];
  34.         str[i] = str[j];
  35.         str[j] = tmp;
  36.  
  37.         i++;
  38.         j--;
  39.     }
  40. }
  41.  
  42. int main(void)
  43. {
  44.     char decimal[256] = "1";
  45.     int i;
  46.  
  47.     for (i = 0; i < 100; i++)
  48.         doubleDecimal(decimal);
  49.  
  50.     reverse(decimal);
  51.     printf("%s", decimal);
  52.  
  53.     return 0;
  54. }
Success #stdin #stdout 0.01s 1676KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
1267650600228229401496703205376
https://ideone.com/dh7QbM
language:
C (gcc 8.3)
created:
11 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!