Create postfix_to_infix.cpp

we can convert postfix to infix expression

Program's_Contributed_By_Contributors/C++ Programs/Stacks/postfix_to_infix.cpp

@@ -0,0 +1,41 @@
+#include <iostream>
+#include <stack>
+#include <string>
+
+using namespace std;
+
+bool isOperator(char c) {
+    return (c == '+' || c == '-' || c == '*' || c == '/');
+}
+
+string postfixToInfix(string postfix) {
+    stack<string> st;
+
+    for (char c : postfix) {
+        if (!isOperator(c)) {
+            st.push(string(1, c));
+        } else {
+            string operand2 = st.top();
+            st.pop();
+            string operand1 = st.top();
+            st.pop();
+
+            string newExpr = "(" + operand1 + " " + c + " " + operand2 + ")";
+            st.push(newExpr);
+        }
+    }
+
+    return st.top();
+}
+
+int main() {
+    string postfixExpression;
+    cout << "Enter a postfix expression: ";
+    cin >> postfixExpression;
+
+    string infixExpression = postfixToInfix(postfixExpression);
+
+    cout << "Infix expression: " << infixExpression << endl;
+
+    return 0;
+}