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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4.     char* __private_to_binary_representation(int n, char* print_here, int pos) {
  5.       //printf("pos %d, n %d\n", pos, n);
  6.       if (n == 0) {
  7.         return print_here;
  8.       }
  9.       print_here = __private_to_binary_representation(n >> 1, print_here, pos + 1);
  10.       (*print_here) = (n & 1) + '0';
  11.       //printf("pos %d, n %d, n & 1 %d, *print_here %c\n", pos, n, n & 1, *print_here);
  12.       return print_here + 1;
  13.     }
  14.  
  15.     char* to_binary_representation(int n, char* print_here) {
  16.       int is_negative = n < 0? 1: 0;
  17.       // primeiro, preencho o valor absoluto do número, então o primeiro bit sempre será 0
  18.       char* null_terminator_pos = __private_to_binary_representation(abs(n), print_here + 1, 0);
  19.       print_here[0] = '0';
  20.  
  21.       // garantindo o final da string
  22.       (*null_terminator_pos) = '\0';
  23.  
  24.       if (is_negative) {
  25.         char* bit_check;
  26.         int bit1_found = 0;
  27.         for (bit_check = null_terminator_pos - 1; bit_check >= print_here; bit_check--) {
  28.           // troca os bits na representação de complemento de 2
  29.           if (bit1_found) {
  30.             (*bit_check) = (*bit_check) == '1'? '0': '1';
  31.           } else if ((*bit_check) == '1') {
  32.             bit1_found = 1;
  33.           }
  34.         }
  35.       }
  36.       return print_here;
  37.     }
  38.  
  39. int main(void) {
  40. 	char buff[100];
  41. 	printf("to_binary_representation(%d), %s\n", 0, to_binary_representation(0, buff));
  42. 	printf("to_binary_representation(%d), %s\n", 1, to_binary_representation(1, buff));
  43. 	printf("to_binary_representation(%d), %s\n", 5, to_binary_representation(5, buff));
  44. 	printf("to_binary_representation(%d), %s\n", -5, to_binary_representation(-5, buff));
  45. 	printf("to_binary_representation(%d), %s\n", -1, to_binary_representation(-1, buff));
  46. 	return 0;
  47. }
  48.  
Success #stdin #stdout 0s 4460KB
comments (?)
stdin
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Standard input is empty
stdout
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to_binary_representation(0), 0
to_binary_representation(1), 01
to_binary_representation(5), 0101
to_binary_representation(-5), 1011
to_binary_representation(-1), 11
https://ideone.com/oasA9A
language:
C (gcc 8.3)
created:
6 years ago
visibility:
secret

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