How can I convert an integer to a hexadecimal string in C

Question

How can I convert an integer to a hexadecimal string in C   Example  The integer 50 would be converted to the hexadecimal string  32  or  0x32

User · Answer

I made a librairy to make Hexadecimal   Decimal conversion without the use of stdio h  Very simple to use    char  dechex  int dec     This will use calloc   to to return a pointer to an hexadecimal string  this way the quantity of memory used is optimized  so don t forget to use free    Here the link on github   https   github com kevmuret libhex

User · Answer

Interesting that these answers utilize printf like it is a given  printf converts the integer to a Hexadecimal string value                                                                      void prntnum unsigned long n  int base  char sign  char  outbuf     unsigned long num   number to be printed    int base          number base for conversion   decimal 10 hex 16    char sign         signed or unsigned output    char  outbuf     buffer to hold the output number                                                                  void prntnum unsigned long n  int base  char sign  char  outbuf         int i   12      int j   0       do          outbuf i     0123456789ABCDEF  num   base           i--          n   num base       while  num  gt  0        if sign                  outbuf 0    sign            j             while    i  lt  13          outbuf j      outbuf i              outbuf j    0

User · Answer

Usually with printf  or one of its cousins  using the  x format specifier

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This code  int a   5  printf   x n   a     prints  5     This code  int a   5   printf  0x x n   a     prints  0x5     This code  int a   89778116  printf   x n   a     prints  559e7c4     If you capitalize the x in the format it capitalizes the hex value   int a   89778116  printf   X n   a     prints  559E7C4     If you want to print pointers you use the p format specifier   char  str    foo   printf  0x p n   str     prints  0x01275744

User · Answer

The following code takes an integer and makes a string out of it in hex format   int  num   32424  char hex 5    sprintf hex    x   num   puts hex     gives  7ea8

User · Answer

To convert an integer to a string also involves char array or memory management   To handle that part for such short arrays  code could use a compound literal  since C99   to create array space  on the fly   The string is valid until the end of the block    define UNS HEX STR SIZE   sizeof  unsigned  CHAR BIT   3  4   1                             compound literal v--------------------------v  define U2HS x  unsigned to hex string  x    char UNS HEX STR SIZE    0   UNS HEX STR SIZE   char  unsigned to hex string unsigned x  char  dest  size t size      snprintf dest  size    X   x     return dest     int main void         3 array are formed v               v        v   printf   s  s  s n   U2HS UINT MAX   U2HS 0   U2HS 0x12345678      char  hs   U2HS rand       puts hs         hs  is valid until the end of the block     Output  FFFFFFFF 0 12345678 5851F42D

[c] How can I convert an integer to a hexadecimal string in C?

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