CODEWITHSUNDEEP
c
AKGhosh
AKGhosh

Reputation: 1

I have written a C code below. I want an explanation on why the output is 34 and not 0 or 42

I would like an explanation on the following code:

#include <stdio.h> 
int main()
{
   int x = 042;
   printf("%d",x);
}

Upvotes: 0

Views: 157

Answers (3)

pankaj maran
pankaj maran

Reputation: 61

adding prefix 0 to any number makes it an octal number. if suppose x equals 096 then the compiler will show an error because 96 is not a valid octal number.

  int x=042;
  printf("%d", x); /* output : 34
  x is in octal representation but %d is used to print for decimal number,
 so 042 change to decimal */

  printf("%o", x); /* output : 42
  %o is used to print in octal representation */

Here, following format specifiers are used:

%d - to print value in integer format

%o - to print value in octal format

%x - to print value in hexadecimal format (letters will print in lowercase)

%X - to print value in hexadecimal format (letters will print in uppercase)

Upvotes: 1

Andrew
Andrew

Reputation: 2322

In the C language, a number prefixed with a zero is considered to be Octal.

ISO/IEC 9899:2018 para 6.4.4.1 Integer constants applies

So, 042 is Octal = 34 decimal.

Upvotes: 0

AKX
AKX

Reputation: 169298

42 in base 8 (octal) is 34 in base 10 (decimal).

Number literals prefixed with zeroes are interpreted as octal in C.

Change 042 to just 42.

Upvotes: 3

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