DSA Assignment 9-infix to postfix.cpp

#include<iostream>
using namespace std;
class stack
{
	char stk[30];

	int top;
public:
	stack()
	{
		top=-1;

	}
	bool is_stack_empty();
	bool is_stack_full();
	void push(char);
	//void push_int(int);
	char pop();
	//int pop_int();
	int priority(char);
	void convert(char[],char[]);
	int evaluate(int,char,int);
	void result_post(char[]);
};
bool stack::is_stack_empty()
{
	if(top==-1)
		return 1;
	else
		return 0;
}

bool stack::is_stack_full()
{
	if(top==29)
		return 1;
	else
		return 0;
}

void stack::push(char ch)
{
	if(is_stack_full())
		cout<<"\n Sorry..stack is full";
	else
	{
		top++;
		stk[top]=ch;
	}
}


char stack::pop()
{
	char temp;
	if(is_stack_empty())
		cout<<"Sorry..stack is empty";
	else
	{
		temp=stk[top];
		top--;
	}
	return temp;
}
int stack::priority(char ch)
{
	if(ch=='(')
		return 0;
	else if(ch=='+' || ch=='-')
		return 1;
	else if(ch=='*' || ch=='/' || ch=='%')
		return 2;
	else if(ch=='^')
		return 3;
}

void stack::convert(char inf[],char post[])
{
	int i;
	int j=0;
	char token,ch;
     for(i=0;inf[i]!='\0';i++)
	{
		token=inf[i];
		if(token=='(')
			push(token);
		else if(token==')')
		{
			for(int i=0;stk[top]!='(';i++)
			{
				//ch=stk[top];
				ch=pop();
				post[j]=ch;
				j++;
			}
		//ch=stk[top];
		ch=pop();
		}
		else if(token=='+'||token=='-'||token=='*'||token=='/'||token=='%'||token=='^')
		{
			if(priority(stk[top])<priority(token))
			{
			push(token);
			}
			else
			{
				while(priority(stk[top])>=priority(token))
				{
				ch=pop();
				post[j]=ch;
				j++;
				//push(token);
				}
				push(token);
			}


		}
		else
		{
			post[j]=token;
			j++;
		}
	}
	while(!is_stack_empty())
	{
		ch=pop();
		post[j]=ch;
		j++;
	}
    post[j]='\0';

}

int stack::evaluate(int op1,char opr,int op2)
{
    if(opr=='+')
        return(op1+op2);
    else if(opr=='-')
        return(op1-op2);
    else if(opr=='*')
        return(op1*op2);
    else if(opr=='/')
        return(op1/op2);
    else if(opr=='%')
        return(op1%op2);
}

void stack::result_post(char post[])
{
    char x;
    int op1,op2,b,val;
    int i=0;
    while(post[i]!='\0')
    {
        x=post[i];
        if(x=='+'||x=='-'||x=='*'||x=='/'||x=='%')
        {
            op2=pop();
            op1=pop();
            val=evaluate(op1,x,op2);
            push(val);

        }
        else
        {
            b=(int)x;
            push(b-48);
        }
        i++;
    }
    val=pop();
    cout<<"\n result is="<<val;
    }





int main()
{
	stack s;
	char inf[30];
	char post[30];
	cout<<"\n Enter infix expression";
	cin>>inf;
	cout<<"\n Given infix expression is:";
	cout<<"\n"<<inf;
	s.convert(inf,post);
	cout<<"\n Conversion of infix to postfix";
	cout<<"\n Postfix expression is:";
	cout<<post;
    cout<<"\n Evaluation of postfix expression is";
    s.result_post(post);
	return 0;
}