Program to convert Infix into Postfix

/* INfix to Postfix*/
#include<stdio.h>
#include<conio.h>
#include<ctype.h>
#include<string.h>
#define SIZE 100

typedef struct STACK
{
char data[SIZE];
int top;

}stack;

void intialize(stack *s);
void push(stack *s,char ch);
char pop(stack *s);
int priority(char ch);
void intopost(stack *s,char infix[]);

int main()
{
   char infix[SIZE];
   stack s;
 
   printf("\n\n Enter the infix string: ");
   scanf("%s",infix);
 
   intopost(&s,infix);
 
   return 0;
}

void intialize(stack *s)
{
s->top=-1;
}
void push(stack *s,char ch)
{
if(s->top != SIZE-1 )
{
s->top++;
s->data[s->top]=ch;
}
}
char pop(stack *s)
{
char ch;
if(s->top != -1)
{
ch=s->data[s->top];
s->top--;
return ch;
}
return 0;
}
int priority(char ch)
{
switch(ch)
{
case '^':
        return 3;
         break;
case '%':
case '/':
case '*':
          return 2;
  break;
case '+':
case '-':
         return 1;
       
default: return 0;
}
}
void intopost(stack *s,char infix[])
{
   char postfix[SIZE],ch;
   int length,i,j=0,k;
     
   intialize(s);
   push(s,'#');
 
   length=strlen(infix);
 
   for(i=0;i<length;i++)
   {
    ch=infix[i];
   
if(ch=='(')
{
push(s,ch);
}
else if(isalnum(ch))
{
postfix[j]=ch;
j++;
}
else if(ch==')')
{
while(s->data[s->top] != '(')
{
postfix[j]=pop(s);
j++;
}
s->top--;
}
else
{
while(priority(ch)<=priority(s->data[s->top]))
{
postfix[j]=pop(s);
j++;
}
push(s,ch);
}
   }
   while(s->data[s->top] != '#' )
   {
    postfix[j]=pop(s);
    j++;
   }
   postfix[j]='\0';
   printf("\n\n The Postfix String: %s",postfix);
}

• Tweet
• Share
• Share
• Share

Related Post