Recursively convert a decimal number to any hexadecimal number

Author: Qing Dujun

Convert a decimal number to any hexadecimal number (2 ~ Between hexadecimal )~

C language:

# Include
 
  
// N: original number (decimal) to: convert to the hexadecimal buf: Save the converted hexadecimal number void fn (int n, int to, char * buf) {// define I as static purpose: to use the same I value static int I = 0 in multi-layer recursion; // in special cases, 0, processing independently if (n = 0) {buf [I] = '0'; return;} // preprocessing of negative numbers if (n <0) {buf [I] = '-'; ++ I; n =-n;} // recursion of positive integers for hexadecimal conversion. if (n! = 0) {// recursive into the stack fn (n/to, to, buf); // recursive elastic stack switch (n % to) {case 15: buf [I] = 'F'; break; case 14: buf [I] = 'E'; break; case 13: buf [I] = 'D'; break; case 12: buf [I] = 'C'; break; case 11: buf [I] = 'B'; break; case 10: buf [I] = 'a '; break; default: buf [I] = (n % to + '0'); break;} + + I ;}} int main () {char buf [50] = ""; int n, to; scanf ("% d", & n, & to); // convert fn (n, to, buf); puts (buf); return 0 ;}
 

C ++ version, optimized the program and reduced some code ~~~

It turns out that when I thought static would define the data type, the right value must be a const value. Of course, this is also true when I tested it in the C environment.

Example:

1) static int a = 0;√

2) static int a = (1 = 2 )? 1: 3;×

However, today I can see that the second form is correct. Later I asked, it turned out to be a. cpp suffix.

During recursion, some execution statements are put into the static statement. Because the static statement is executed only once and some are put in the statement, it is better to execute only once ~~~~

The following code is displayed in. CppFile,. CAn error is reported ~~~

# Include
 
  
// N: original number (decimal) to: convert to the hexadecimal char * fn (int n, int to) {// define the purpose of static variables: to use the same value in multi-layer recursion, and perform static char buf [100] = "", BinHex [] = {'0', '1 ', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B ', 'C', 'D', 'E', 'F'}; // handle n = 0 and n <0, static: Only one static int I = (n> = 0 )? (Buf [0] = '0', 0): (buf [0] = '-', n =-n, 1); // positive integer recursion, perform hexadecimal conversion. if (n! = 0) {// recursive into the stack fn (n/to, to); // recursive pop-up stack buf [I ++] = BinHex [n % to];} return buf;} int main () {char * buf = NULL; int n, to; // input n: original data: the hexadecimal scanf ("% d", & n, & to) to be converted; // The hexadecimal conversion buf = fn (n, ); puts (buf); return 0 ;}
 

Of course, the above Code does not process more than hexadecimal and less than binary ~~~~

References: SnailSet blog column, converts decimal integers into B-hexadecimal strings (recursive and non-recursive implementations), http://blog.csdn.net/snailset/article/details/26492715