Conversion Infix to post fix - User Input

This a C++ implementation to convert infix expression to postfix where system takes infix expression as an input from the user.
The operators that are used in this code are { +, -, *, /, ^, $ )
Here the precedence of operators are as follow : 
'$' > '^' > '*' AND '/' > '+'  AND '-'

Author: pranav7955

Data Structures/Stack/Conversion Infix to post fix - User Input.cpp

@@ -0,0 +1,98 @@
+/* C++ implementation to convert infix expression to postfix, system takes infix expression from the user as an input */
+
+#include<bits/stdc++.h>
+#include <stack>
+#include <string>
+using namespace std; 
+
+//Function to return precedence of operators 
+int prec(char c) 
+{ 
+	if(c == '$') 
+	return 4;
+  else if(c == '^') 
+	return 3;
+	else if(c == '*' || c == '/') 
+	return 2; 
+	else if(c == '+' || c == '-') 
+	return 1; 
+	else
+	return -1; 
+} 
+
+// The main function to convert infix expression 
+//to postfix expression 
+void infixToPostfix(string s) 
+{ 
+	stack<char> st; 
+	st.push('N'); 
+	int l = s.length(); 
+	string ns; 
+	for(int i = 0; i < l; i++) 
+	{ 
+		// If the scanned character is an operand, add it to output string. 
+		if((s[i] >= 'a' && s[i] <= 'z')||(s[i] >= 'A' && s[i] <= 'Z')) 
+		ns+=s[i]; 
+
+		// If the scanned character is an ‘(‘, push it to the stack. 
+		else if(s[i] == '(') 
+		
+		st.push('('); 
+		
+		// If the scanned character is an ‘)’, pop and to output string from the stack 
+		// until an ‘(‘ is encountered. 
+		else if(s[i] == ')') 
+		{ 
+			while(st.top() != 'N' && st.top() != '(') 
+			{ 
+				char c = st.top(); 
+				st.pop(); 
+			ns += c; 
+			} 
+			if(st.top() == '(') 
+			{ 
+				char c = st.top(); 
+				st.pop(); 
+			} 
+		} 
+		
+		//If an operator is scanned 
+		else{ 
+			while(st.top() != 'N' && prec(s[i]) <= prec(st.top())) 
+			{ 
+				char c = st.top(); 
+				st.pop(); 
+				ns += c; 
+			} 
+			st.push(s[i]); 
+		} 
+
+	} 
+	//Pop all the remaining elements from the stack 
+	while(st.top() != 'N') 
+	{ 
+		char c = st.top(); 
+		st.pop(); 
+		ns += c; 
+	} 
+	
+	cout << ns << endl; 
+
+} 
+
+//Driver program to test above functions 
+int main() 
+{ 
+    
+	string exp;
+	cout << "Please enter the infix expression you need to convert: \n";
+	getline (cin,exp);// Get the infrix expression as an input from the user
+  /* EXAMPLE OF SOME INFIX EXPRESSIONS : 
+  a+b
+  (a+b)*c
+  (A+B)*(C+D)
+  */
+	infixToPostfix(exp); 
+	return 0; 
+} 
+