#include<stdio.h>
#include<string.h>

int F(char symbol)
{
	switch (symbol)
	{
	case '+':
	case '-':return 2;
	case '*':
	case '/':
	case '%':return 4;
	case '^':
	case '$':return 5;
	case '(':return 0;
	case '#':return -1;
	default :return 8;
	}
}

int G(char symbol)
{
	switch (symbol)
	{
	case '+':
	case '-':return 1;
	case '*':
	case '/':
	case '%':return 3;
	case '^':
	case '$':return 6;
	case '(':return 3;
	case ')':return 0;
	default :return 7;
	}
}

void infix_postfix(char infix[], char postfix[])
{
int top=-1, j=0, i;
char s[30], symbol;
s[++top] = '#';
for(i=0; i < strlen(infix); i++)
{
	symbol = infix[i];
	while (F(s[top]) > G(symbol))
	{
		postfix[j] = s[top--];
		j++;
	}
	if(F(s[top]) != G(symbol))
		s[++top] = symbol;
	else
		top--;
}
while(s[top] != '#')
	postfix[j++] = s[top--];
postfix[j] = '\0';
}

void main()
{
char infix[20], postfix[20];
printf("\nEnter a valid infix expression\n") ;
scanf ("%s", infix) ;
infix_postfix (infix, postfix);
printf("\nThe infix expression is:\n");
printf ("%s",infix);
printf("\nThe postfix expression is:\n");
printf ("%s",postfix) ;
}
