/*初学c时整的，这是一个计算器的程序清单*/
#define MAX 50
#include<math.h>
#include<stdlib.h>
#include<stdio.h>
#include<conio.h>
#include<bios.h>
#include<dos.h>
char OP[10]={'+','-','*','/','^','(',')','='};
int m;
typedef struct
{float q[MAX];
int top;
}NUMBER;
typedef struct
{char q[MAX];
int top;
}CHARACTOR;
void initstack1(NUMBER *s1);
void initstack2(CHARACTOR *s2);
int stackemty1(NUMBER s1);
int stackemty2(CHARACTOR s2);
void push1(NUMBER *s1,float e);
void push2(CHARACTOR *s2,char e);
void pop1(NUMBER *s1,float *e);
void pop2(CHARACTOR *s2,char *e);
int isp(char x);
int iesp(char x);
void drawpicture(void);
void getcher(char exp[]);
float evaluate(char exp[]);
void Help(void);
void main()
{ char exp[MAX]={0};
char j;
float v;
int k;
fflush(stdin);
do{
clrscr();
drawpicture();
gotoxy(1,19);
printf("
ress the 'F1' to get the help information!");gotoxy(2,3);
getcher(exp);
v=evaluate(exp);
printf("=%f\n",v);
gotoxy(1,19);
clreol();
printf("continue?y/n
put y to continue,n to out)");j=getch();
fflush(stdin);
}while(j=='y');
}
void initstack1(NUMBER *s1)
{ (*s1).top=-1;}
void initstack2(CHARACTOR *s2)
{ (*s2).top=-1;}
int stackemty1(NUMBER s1)
{if(s1.top==-1)return 1;else return 0;}
int stackemty2(CHARACTOR s2)
{if(s2.top==-1)return 1;else return 0;}
void push1(NUMBER *s1,float e)
{if((*s1).top==MAX-1)
{printf("FULL\n");return;}
(*s1).q[++((*s1).top)]=e;
}
void push2(CHARACTOR *s2,char e)
{if((*s2).top==MAX-1)
{printf("FULL\n");return;}
(*s2).q[++((*s2).top)]=e;
}
void pop1(NUMBER *s1,float *e)
{if((*s1).top==-1){printf("the stack is empty\n");return;}
*e=(*s1).q[(*s1).top--];
}
void pop2(CHARACTOR *s2,char *e)
{if((*s2).top==-1){printf("the stack is empty\n");return;}
*e=(*s2).q[(*s2).top--];
}
int isp(char x)
{int i;
if(x=='^') {i=3;}
else if(x=='*'||x=='/') {i=2;}
else if(x=='+'||x=='-') {i=1;}
else if(x=='(') {i=0;}
return i;
}
int iesp(char x)
{int i;
if(x=='^') {i=4;}
else if(x=='*'||x=='/') {i=2;}
else if(x=='+'||x=='-') {i=1;}
else if(x=='(') {i=4;}
return i;
}
void drawpicture(void)
{
");
printf(" 图略 ");
gotoxy(2,3);
}
void Help(void)
{
gotoxy(1,20);
printf("HELP");
printf("1.put the express like this:3*2^(4+2*2-6)-5;\n");
printf("2.You can use '0' to '9' and '+','_','*','/','^','.'\n");
printf("3.press the <- and -> to add and delete the number;\n");
printf("4.put the 'backpace' to delete the numbber\n");
printf("4.when you put off the express,push the 'Enter' to calulate!\n");
printf("5.you can press 'Esc' to end the program!\n");
}
int In(char c)
{
int i=0;
while(i<8)
{
if(c==OP[i++])
return 1;
}
return 0;
}
void getcher(char exp[])
{ int i=0,j=0,k;
char I;
int count1=0,count2=0;
for(;i!=0x1c0d;)
{ i=bioskey(0);
I=i;
if(i==0xe08||i==0x5300)
{ j--;
printf("\b \b");
continue;}
else if((i&0x00ff)==27)
{
exit(0);
}
else if(i==0x3b00) //f1
{
Help();
gotoxy(2+j,3);
continue;
}
else if(j>=0)
{
if(((i&0x00ff)!=0)&&(i!=0x1c0d))
{
exp[j++]=I;
printf("%c",I);
}
else
{ if(i==0x4b00)
{
gotoxy(1+j--,3);
}
else if(i==0x4d00)
{gotoxy(1+j++,3);}
else if(i==0x1c0d)
{exp[j++]='=';}
else
{clrscr();
printf("Wrong! Please check");break;
}//else
}//else
}// else if
}//for
for(i=0;i<j;i++)
{
if(exp=='(')
count1++;
if(exp==')')
count2++;
}
if(count1!=count2)
{
printf("the (,) are not match.The program will exit in 200 ms!");
delay(2000);
exit(-1);
}
m=j;
}//getchar
float Operate(float a,char e,float b)
{
float t;
switch(e)
{
case '+':t=a+b;break;
case '-':t=a-b;break;
case '*':t=(a)*(b);break;
case '/':t=(a)/(b);break;
case '^':t=pow(a,b);break;
}
return t;
}
float evaluate(char exp[])
{
NUMBER s1;
CHARACTOR s2;
int n,j=0;
int count;
float x,a,b,v;
char c,e,r;
initstack1(&s1);
initstack2(&s2);
push2(&s2,'(');
while(1)
{
n=j;
for(j=n;j<m;j++)
{
r=exp[j];
if(!In(r))
{
sscanf(exp+j,"%f",&x);
while(1)
{
j++;
if(In(exp[j]))
break;
} //while
push1(&s1,x);
break;
} //if
else
{
sscanf(exp+j,"%c",&c);
switch(c)
{
case ')':while(s2.q[s2.top]!='(')
{
pop2(&s2,&e);
pop1(&s1,&b);
pop1(&s1,&a);
push1(&s1,Operate(a,e,b));
} //while
pop2(&s2,&c);
break;
case '=': while(s2.top!=0)
{
pop2(&s2,&e);
pop1(&s1,&b);
pop1(&s1,&a);
push1(&s1,Operate(a,e,b));
}
pop1(&s1,&v);
return v;
default:
while(iesp(c)<=isp(s2.q[s2.top]))
{
pop2(&s2,&e);
pop1(&s1,&b);
pop1(&s1,&a);
push1(&s1,Operate(a,e,b));
}
push2(&s2,c);
break;
}//switch
} //else
}//for
}//while
}
（有点 长了阿，算法还需要改进）
呵呵
