· KLDP.org · KLDP.net · KLDP Wiki · KLDP BBS ·
GCM

G.C.M. (Greatest Common Measure, 최대공약수 구하기)

설명

두 정수간의 최대공약수를 구하는 코드입니다. 배보다 배꼽이 더 커진것 같은데 철저한 테스트를 위해서 배꼽이 커졌네요.

사용방법

gcm.c 로 소스를 저장후 컴파일은 요렇게 합니다.
bash# gcc -o gcm gcm.c


코드

/* 
  Copyright (C) JAEHYUK CHO
  All rights reserved.
  Code by JaeHyuk Cho <mailto:minzkn@minzkn.com>
*/ 

#include <stdio.h> 

#if 0 
typedef unsigned int t_gcm_value; 
#else 
typedef int t_gcm_value; 
#endif 

static t_gcm_value _gcm_to_abs(t_gcm_value s_value) 
{ 
 static t_gcm_value sg_msb = (((t_gcm_value)1) << ((sizeof(t_gcm_value) << 3) - 1)); 
 t_gcm_value s_temp; 
 s_temp = sg_msb >> ((sizeof(t_gcm_value) << 3) - 1); 
 if(s_temp != ((t_gcm_value)1)) 
 { /* t_gcm_value is signed type */ 
  if((s_value & sg_msb) == sg_msb) 
  { /* s_value < 0 */ 
   s_value = -s_value; 
  } 
 } 
 return(s_value); 
} 

static t_gcm_value _gcm(t_gcm_value s_value1, t_gcm_value s_value2) 
{ 
 t_gcm_value s_temp; 
 if(s_value1 < s_value2) 
 { /* swap */ 
  s_temp = s_value1; 
  s_value1 = s_value2; 
  s_value2 = s_temp; 
 } 
 do 
 { 
  s_temp = s_value1 % s_value2; 
  if(s_temp == ((t_gcm_value)0))break; 
  s_value1 = s_value2; 
  s_value2 = s_temp; 
 }while(1); 
 return(_gcm_to_abs(s_value2)); 
} 

void gcm(t_gcm_value s_value1, t_gcm_value s_value2) 
{ 
 t_gcm_value s_value; 
 s_value = _gcm(s_value1, s_value2); 
 (void)fprintf(stdout, "gcm(%ld, %ld) = %ld\n", 
  (long)s_value1, (long)s_value2, (long)s_value); 
} 

int main(void) 
{ 
 /* test suite */ 
    
 gcm(8, 12); 
 gcm(12, 8); 
 gcm(12, 18); 
 gcm(3, 2); 
 gcm(100, 200); 
 gcm(300, 124); 

 (void)fprintf(stdout, "\n"); 
  
 gcm(-8, -12); 
 gcm(-12, -8); 
 gcm(-12, -18); 
 gcm(-3, -2); 
 gcm(-100, -200); 
 gcm(-300, -124); 
  
 (void)fprintf(stdout, "\n"); 
  
 gcm(-8, 12); 
 gcm(-12, 8); 
 gcm(-12, 18); 
 gcm(-3, 2); 
 gcm(-100, 200); 
 gcm(-300, 124); 
  
 (void)fprintf(stdout, "\n"); 
  
 gcm(8, -12); 
 gcm(12, -8); 
 gcm(12, -18); 
 gcm(3, -2); 
 gcm(100, -200); 
 gcm(300, -124); 
  
 (void)fprintf(stdout, "\n"); 
  
 gcm(0xffffffff, 0xffffffff); 

 return(0); 
} 

/* End of source */

ID
Password
Join
If it pours before seven, it has rained by eleven.


sponsored by andamiro
sponsored by cdnetworks
sponsored by HP

Valid XHTML 1.0! Valid CSS! powered by MoniWiki
last modified 2012-01-26 11:06:57
Processing time 0.0036 sec