// Program for infix to postfix conversion.
#include<stdio.h>
char ifix[200],pfix[200],stack[100];
int p=0,s=0,i=0;
void fun()
{
if(ifix[i]==')')
{
s--;
while(stack[s]!='(')
pfix[p++]=stack[s--];
}
if(ifix[i]=='+' || ifix[i]=='-')
{
if(!s)
stack[s++]=ifix[i];
else if(stack[s-1]=='(')
stack[s++]=ifix[i];
else
{
s--;
while(s!=-1 && stack[s]!='(')
{
pfix[p++]=stack[s--];
}
stack[++s]=ifix[i];
s++;
}
}
}
int main()
{
printf("Enter your infix expression(using operators +, -, %%, /, *) : ");
scanf("%s",ifix);
for(i;ifix[i]!='\0';i++)
{
if(ifix[i]!='*' && ifix[i]!='/' && ifix[i]!='-' && ifix[i]!='+' && ifix[i]!='(' && ifix[i]!=')' && ifix[i]!='%')
pfix[p++]=ifix[i];
else if(ifix[i]=='(' || ifix[i]=='*' || ifix[i]=='/' || ifix[i]=='%')
stack[s++]=ifix[i];
else
fun();
}
if(ifix[i]=='\0')
{
if(s)
{
s--;
while(s!=-1)
{
if(stack[s]==')' || stack[s]=='(')
s--;
pfix[p++]=stack[s--];
}
}
pfix[p]='\0';
}
printf("The postfix expression is : %s",pfix);
return 0;
}
