经典c程序(0031) ---中缀表达式转后缀表达式并求值

#include<stdio.h>         
/*******************************************************************************/
#define M 300
char express[M];
char string[M];
int  len=0;
/*******************************************************************************/
int express_calc(char *express,int len);
/*******************************************************************************/
typedef struct{
	char cstore[M];
	int  ctop;
}Stack_ct;
void stack_cinit( Stack_ct * A)
{
	(*A).ctop=-1;
}
int  stack_cpush(Stack_ct * A,char val)
{
	if( (*A).ctop==M-1 )// stack full, cannot push
		return (-1);
	(*A).cstore[  ++((*A).ctop) ]=val;
}
int stack_cpop(Stack_ct *A,char *val)
{
	if( (*A).ctop==-1 )// stack empty, cannot pop
		return (-1);
	*val=(*A).cstore[  ((*A).ctop)-- ];
}
Stack_ct token_store;
/*******************************************************************************/
typedef struct{
	int istore[M];
	int  itop;
}Stack_it;
void stack_iinit( Stack_it *A)
{
	(*A).itop=-1;
}
int  stack_ipush(Stack_it * A,int val)
{
	if( (*A).itop==M-1 )// stack full, cannot push
		return (-1);
	(*A).istore[  ++((*A).itop) ]=val;
}
int stack_ipop(Stack_it *A,int *val)
{
	if( (*A).itop==-1 )// stack empty, cannot pop
		return (-1);
	*val=(*A).istore[  ((*A).itop)-- ];
}
Stack_it intstore;
/*******************************************************************************/
int comp_pri_before(char x, char y)
{
	char token[5]={'+','-','*','/','('};
	int  before_pri[5]={1,1,2,2,3};
	int  i=0,a=0,b=0;
	for(i=0;i<5;i++)
	{
		if(x==token[i])
			a=i;
		if(y==token[i])
			b=i;
	}
	if( before_pri[a] > before_pri[b])
		return (1);
	else
		return (0);
}
/*
int comp_pri_after(char x, char y)
{
	char token[5]={'+','-','*','/','('};
	int  after_pri[5]={1,1,2,2,0};
	int  i=0,a=0,b=0;
	for(i=0;i<5;i++)
	{
		if(x==token[i])
			a=i;
		if(y==token[i])
			b=i;
	}
	if( after_pri[a] > after_pri[b])
		return (1);
	else
		return (0);
}
*/
/*******************************************************************************/
int calc(int a, int b, char c)
{
	switch(c)
	{
	case '+':
		return (a+b);
	case '-':
		return (a-b);
	case '*':
		return (a*b);
	case '/':
		return (a/b);
	default:
		;//return NULL;
	}
}
/*******************************************************************************/
int main(void)
{
	int test_case;
	int T=0,th=1;

	freopen("input.txt", "r", stdin);
	setbuf(stdout, NULL);
	//scanf("%d", &T);
	T=10;
	for(test_case = 0; test_case < T; test_case++)
	{
		int ret=0;
		/**********************************
		 * Implement your algorithm here. */
		scanf("%d",&len);
		scanf("%s",express);
		ret=express_calc(express,len);
		/**********************************/
		// Print the answer to standard output(screen).
		printf("#%d %d\n",th++,ret);
	    fflush(stdout);//修复Eclipse printf（）不能显示的小bug  
	}
	return (0);//Your program should return 0 on normal termination.
}
  
int express_calc(char *express,int len)
{
	int i=0,j=0,k=0,sum=0,a=0,b=0;
	char tmp;
	char stoken[14]={'0','1','2','3','4','5','6','7','8','9','+','-','*','/'};
	for(i=0;i<len;i++)
		string[i]='\0';
	stack_cinit( &token_store);
	stack_iinit( &intstore);
	for(i=0;i<len;i++)
	{
		if( express[i]>=48 && express[i]<=57)// number
			string[k++]=express[i];
		else//char
		{
			if(express[i]==')')
			{
				tmp=token_store.cstore[token_store.ctop];
				while(tmp !='(')
				{
					stack_cpop(&token_store,&string[k++]);
					tmp=token_store.cstore[token_store.ctop];
				}
				stack_cpop(&token_store,&tmp);
				continue;
			}
			if( token_store.ctop==-1)
				stack_cpush(&token_store,express[i]);
			else
			{
				tmp=token_store.cstore[token_store.ctop];
				if(tmp=='(')///////////////////////////////////////lost
				{
					stack_cpush(&token_store,express[i]);
					continue;
				}
				if( comp_pri_before(express[i],tmp)  )
					stack_cpush(&token_store,express[i]);
				else
				{
					tmp=token_store.cstore[token_store.ctop];
					while( ! comp_pri_before(express[i],tmp)  )
					{
						if(token_store.ctop==-1 || tmp=='(')
							break;
						stack_cpop(&token_store,&string[k++]);
						tmp=token_store.cstore[token_store.ctop];
					}
					stack_cpush(&token_store,express[i]);
				}
			}
		}
	}
	while(token_store.ctop!=-1)
	{
		stack_cpop(&token_store,&string[k++]);
	}
   /////////////////////////////////////////////////////////////////////////////////////
	i=0;
	for(i=0;i<len;i++)
	{
		for(j=0;j<14;j++)
		{
			if( string[i] ==stoken[j] )
				break;
		}
		if(j==14)
			break;
		if( string[i]>=48 && string[i]<=57 )
			stack_ipush(&intstore,string[i]-48);
		else{
			stack_ipop(&intstore,&a);
			stack_ipop(&intstore,&b);
			sum=calc(b,a,string[i]);
			stack_ipush(&intstore,sum);
		}
	}
	sum=intstore.istore[intstore.itop];
	return (sum);
}