尝试使用c中的递归将十进制转换为二进制转换器

Question

and i need to make a decimal to binery converter in c with recursion but the output is wrong ex decimal = 22, correct binary = 10110, output = 01101

so this is the code that i came up with

#include <stdio.h>

int biner (int a){


    if (a == 1)
    return 1;

    else if (a % 2 == 1)
    {
    printf ("1");
    return biner (a / 2);
    }


    else
    {
    printf ("0");
    return biner (a / 2);
    }



}


int main () {
    int a;
    printf ("Masukan angka ");
    scanf ("%d", &a);


    printf ("%d", biner (a));



}

which part do i need to change thanks in advance

Answer 1

OP's code output is in the wrong order as it needs to recurse before printing to print the most significant digits first.

Instead of

printf ("1");   // prints least significant digit
biner (a / 2);  // prints most significant digits

More like

biner (a / 2);  // prints most significant digits
printf ("1");   // prints least significant digit

---

There really is no need to return a value, let biner() can do all printing.

As code is not attempting to print a sign , might as well use unsigned a .

OP's code recurses endlessly if a == 0 . Only recurse if a >= 1 . ( a binary digit exist to the left.)

With d as 0 or 1, The binary digit to print can use putchar('0' + d)

Suggested simplification:

#include <stdio.h>

void biner(unsigned a) {
  if (a > 1) {   // Do binary digits exist to the left?
    biner(a/2);  // Print them.
  }
  putchar('0' + a%2);  // Now print the least significant digit.
}

int main(void) {
  unsigned a;
  printf("Masukan angka ");
  scanf("%u", &a);

  biner(a);
  putchar('\n');
}