#include <iostream>
#include<ctype.h>
using namespace std;
#define Max 20
int priority(char ch);
class InfixToPostfix
{
};
class Stack{
char stack[Max];
public:
int top = 0;
void push(char value)
{
if(top == Max-1)
{
cout<<"Stack Overflow"<<"\n";
return;
}
top++;
stack[top] = value;
}
char pop()
{
if(top == -1)
{
cout<<"Stack Underflow"<<"\n";
return -1;
}
char value = stack[top];
top--;
return value;
}
char peek()
{
return stack[top];
}
};
int priority(char ch)
{
if(ch=='^') return 3;
if(ch == '*' || ch =='%' || ch == '/' ) return 2;
if(ch == '+' || ch == '-') return 1;
return 0;
}
int main() {
char infix[] = "((A+B)*(C-D))+(F-G)";
// for(int i=0;i<10;i++)
// cout<<infix[i];
char reverseinfix[20];
for(int i=0;i<20;i++)
{
if(infix[19-i]==')'){
reverseinfix[i] = '(';continue;}
if(infix[19-i]=='('){
reverseinfix[i] =')'; continue;}
reverseinfix[i] = infix[19-i];
}
for(int i=0;i<20;i++)
cout<<reverseinfix[i];
cout<<"\n";
char postfix[20];
char prefix[20];
int p_index = 0;
Stack src;
for(int i=0;i<20;i++)
{
if(reverseinfix[i]=='(') {
src.push(reverseinfix[i]);
continue;
}
if(reverseinfix[i]==')')
{
char ch = src.pop();
while(ch != '(' && src.top!=-1)
{
postfix[p_index]= ch;
p_index++;
ch = src.pop();
}
continue;
}
if(reverseinfix[i]=='+'||reverseinfix[i]=='-'||reverseinfix[i]=='*'||reverseinfix[i]=='/'||reverseinfix[i]=='%'||reverseinfix[i]=='^')
{
if(src.top!=-1)
{
char op = src.pop();
while(priority(op)>=priority(reverseinfix[i]) && src.top!=-1)
{
postfix[p_index]= op;
p_index++;
op = src.pop();
}
src.push(op);
src.push(reverseinfix[i]);
}
else
{
src.push(reverseinfix[i]);
}
continue;
}
if(isdigit(reverseinfix[i]) || isalpha(reverseinfix[i])){
postfix[p_index]= reverseinfix[i];
p_index++;
continue;
}
}
while(src.top!=-1)
{
char ch = src.pop();
postfix[p_index] = ch;
p_index++;
}
for(int i=0;i<p_index;i++)
{
prefix[i] = postfix[p_index-i];
}
for(int i=0;i<p_index;i++)
{
cout<<prefix[i];
}
return 0;
}
