evaluate Prefix Expression in C | C Program to show evaluate Prefix Expression in C | evaluate Prefix Expression in C Example

evaluate Prefix Expression in C | C Program to show evaluate Prefix Expression in C | evaluate Prefix Expression in C Example




#include
#include
#include
#include

#define MAX 30
#define OPERAND 10
#define OPERATOR 20

typedef struct prexp
{
int top;
int stack[MAX];
}stck;

void init(stck*);
void push(stck*,int);
int pop(stck*);
void eval(stck*,char,int,int);
int gettype(char);
void main()
{
char pre[MAX];
int num1,num2,item,l,i,pr;
stck stk;

fflush(stdin);
clrscr();

init(&stk);
printf(" ENTER THE PREFIX EXPRESSION ");
gets(pre);
l=strlen(pre);

for(i=l-1;i>=0;i--)
{
if(pre[i]==' ' || pre[i]=='\0')
continue;
switch(gettype(pre[i]))
{
case OPERAND : item=pre[i]-'0';
push(&stk,item);
break;
case OPERATOR : num1=pop(&stk);
num2=pop(&stk);
eval(&stk,pre[i],num1,num2);
}
}
printf("%d",stk.stack[0]);
getch();
}

void init(stck *st )
{
st->top=-1;
}

void push(stck *st,int num)
{
st->top++;
st->stack[st->top]=num;
}

int pop(stck *st)
{
int num;
num=st->stack[st->top];
st->top--;
return num;
}

void eval(stck *st,char op,int num1,int num2)
{
int res;
switch(op)
{
case '+': res=num1+num2;
break;
case '-': res=num1-num2;
break;
case '*': res=num1*num2;
break;
case '/': res=num1/num2;
break;
case '%': res=num1%num2;
break;
case '$': res=pow(num1,num2);
break;
}
push(st,res);
}

int gettype(char c)
{
switch(c)
{
case '+':
case '-':
case '*':
case '/':
case '$':
case '%': return OPERATOR;
default : return OPERAND;
}
}



Related Links :

No comments:

Post a Comment


If you face any Problem in viewing code such as Incomplete "For Loops" or "Incorrect greater than or smaller" than equal to signs then please collect from My Web Site CLICK HERE


More Useful Topics...

 

History Of C..

In the beginning was Charles Babbage and his Analytical Engine, a machine
he built in 1822 that could be programmed to carry out different computations.
Move forward more than 100 years, where the U.S. government in
1942 used concepts from Babbage’s engine to create the ENIAC, the first
modern computer.
Meanwhile, over at the AT&T Bell Labs, in 1972 Dennis Ritchie was working
with two languages: B (for Bell) and BCPL (Basic Combined Programming
Language). Inspired by Pascal, Mr. Ritchie developed the C programming
language.

My 1st Program...


#include
#include
void main ()
{
clrscr ();
printf ("\n\n\n\n");
printf ("\t\t\t*******Pankaj *******\n");
printf ("\t\t\t********************************\n");
printf ("\t\t\t\"Life is Good...\"\n");
printf ("\t\t\t********************************");
getch ();
}

Next Step...


#include
#include

void main ()
{
clrscr ();
printf ("\n\n\n\n\n\n\n\n");
printf ("\t\t\t --------------------------- \n\n");

printf ("\t\t\t | IGCT, Info Computers, INDIA | \n\n");
printf ("\t\t\t --------------------------- ");

getch ();

}

Hits!!!