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+