Expression Tree - Convert infix to Post expression Program with Output

Program : 

#include <stdio.h>

#include <conio.h>

#include <string.h>

#include <ctype.h>

char stack[100];

int top=0;

char exp[100];

struct table

{

char s[2];

int isp;

int icp;

}pr[7];

int isp(char c)

{

int i;

for(i=0;i<=6;i++)

if(pr[i].s[0]==c)

return(pr[i].isp);

return 0;

}

int icp(char c)

{

int i;

for(i=0;i<=6;i++)

if(pr[i].s[0]==c)

return(pr[i].icp);

return 0;

}

void main()

{

int i;

clrscr();

strcpy(pr[0].s,"^");

pr[0].isp=3;

pr[0].icp=4;



strcpy(pr[1].s,"*");

pr[1].isp=2;

pr[1].icp=2;



strcpy(pr[2].s,"/");

pr[2].isp=2;

pr[2].icp=2;

strcpy(pr[3].s,"+");

pr[3].isp=1;

pr[3].icp=1;



strcpy(pr[4].s,"-");

pr[4].isp=1;

pr[4].icp=1;



strcpy(pr[5].s,"(");

pr[5].isp=0;

pr[5].icp=4;



strcpy(pr[6].s,"=");

pr[6].isp=-1;

pr[6].icp=0;



clrscr();

stack[top]='=';

printf("enter the infix expression");

gets(exp);

 i=0;

printf("the postfix expression is ")

while(i<strlen(exp))

 {

if(isalpha(exp[i])==0)

 {



if(exp[i]==')')

       {

            while(stack[top]!='(')

                        {

                        printf("%c",stack[top]);

                        top--;

                        }

                        top--;

       }

else

             {

            while(isp(stack[top])>=icp(exp[i]))

               {

            printf("%c",stack[top]);

            top--;

               }

            top++;

            stack[top]=exp[i];

             }

  }

else

printf("%c",exp[i]);

i++;

 }

while(top>0)

 {

printf("%c",stack[top]);

top--;

 }

getch();
}

Output: 

Enter the infix expression a*(s+d/f)+c
The postfix expression is asdf/+*c+