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Reply-To: "Masato Kagotani" <kagotani@ma.sa.to>
From: "Masato Kagotani" <kagotani@ma.sa.to>
To: <kashi@mn.waseda.ac.jp>
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Date: Thu, 20 May 1999 01:53:38 +0900
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とりあえず数式を総当たりで作って
それをそのまま計算するプログラムです
したがって同じ順番が入れ替わっただけの同じ数式も
別の物として出力されます

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#define X 10
#define N 4
double expression(void);
char exp[256];
int exp_c=0;
int Q;
int error;
void fwd(void)
{
 if((Q=exp[exp_c++])==NULL)return;
}
double number(void)
{
 double x;
 int sign='+';

 if(Q=='+' && Q=='-')
 {
  sign=Q;
  fwd();
 }
 x=Q-'0';
 while(fwd(),isdigit(Q))x=10*x+Q-'0';
 if(sign=='-')return -x;else return x;
}
double factor(void)
{
 return number();
}
double term(void)
{
 double x,y;
 x=factor();
 for(;;)
 {
  switch(Q)
  {
   case '*':fwd();x*=factor();break;
   case '/':fwd();y=factor();if(y!=0){x/=y;}else{error=1;}break;
   default:return x;
  }
 }
}
double expression(void)
{
 double x;
 x=term();
 for(;;)
 {
  switch(Q)
  {
   case '-':fwd();x-=term();break;
   case '+':fwd();x+=term();break;
   default:return x;
  }
 }
}
double excute(char *s)
{ int x;
 exp_c=0;
 strcpy(exp,s);
 error=0;
 fwd();
 x=(int)expression();
 if(x==X && error==0)printf("%s=%d\n",exp,x);
 return 0;
}
char chr[11]="0123456789";
char cal[5]="+-*/";
void generate(char *t,int depth)
{
 int c;
 if(depth==(N*2-1))
 {
  t[depth]=0;
  excute(t);
  return;
 }
 if((depth%2)==0)
 {
  for(c=0;c<10;c++)
  {
   t[depth]=chr[c];
   generate(t,++depth);
   depth--;
  }
 }else{
  for(c=0;c<4;c++)
  {
   t[depth]=cal[c];
   generate(t,++depth);
   depth--;
  }
 }
 
}
void main(void)
{
 char text[N*3];
 generate(text,0);
}