Fix parentheses_checker.cpp: remove <bits/stdc++.h>, support multi-line input, add comments (#8760)

Cpp/Parentheses_Checker.cpp

@@ -1,52 +1,49 @@
 // parentheses_checker.cpp
-// Compile with: g++ -std=c++17 parentheses_checker.cpp -o parentheses_checker
+// A simple program to check whether the parentheses/brackets/braces
+// in each input line are balanced.
+// Compile: g++ -std=c++17 parentheses_checker.cpp -o parentheses_checker
 
-#include <bits/stdc++.h>
+#include <iostream>
+#include <stack>
+#include <string>
 using namespace std;
 
+// Function to check if two brackets are a matching pair
 bool isMatching(char open, char close) {
-    return (open == '(' && close == ')')
-        || (open == '[' && close == ']')
-        || (open == '{' && close == '}');
+    return (open == '(' && close == ')') ||
+           (open == '[' && close == ']') ||
+           (open == '{' && close == '}');
 }
 
+// Function that checks if parentheses in a string are balanced
 bool areParenthesesBalanced(const string &s) {
     stack<char> st;
     for (char ch : s) {
         if (ch == '(' || ch == '[' || ch == '{') {
             st.push(ch);
         } else if (ch == ')' || ch == ']' || ch == '}') {
-            if (st.empty() || !isMatching(st.top(), ch)) {
-                return false; // closing bracket without matching opening
-            }
+            if (st.empty() || !isMatching(st.top(), ch))
+                return false; // unmatched closing bracket
             st.pop();
-        }
-        // ignore other characters
+        } 
+        // Ignore non-bracket characters
     }
-    return st.empty(); // balanced iff nothing left unmatched
+    return st.empty(); // Balanced if stack is empty at the end
 }
 
 int main() {
     ios::sync_with_stdio(false);
     cin.tie(nullptr);
 
-    cout << "Enter string to check (single line). Press Ctrl+D/Ctrl+Z to end:\n";
-    string line;
-    // Read whole line (including spaces). For multiple tests, loop or read until EOF.
-    if (!getline(cin, line)) return 0;
-
-    bool balanced = areParenthesesBalanced(line);
-    if (balanced) cout << "Balanced\n";
-    else cout << "Not Balanced\n";
+    cout << "Enter multiple lines to check parentheses balance.\n";
+    cout << "Press Ctrl+D (Linux/Mac) or Ctrl+Z (Windows) to finish input.\n\n";
 
-    // Example quick tests (uncomment to run built-in tests)
-    /*
-    vector<string> tests = {
-        "()[]{}", "([{}])", "(]", "([)]", "a + (b - c) * {d / [e + f]}"
-    };
-    for (auto &t : tests) {
-        cout << t << " -> " << (areParenthesesBalanced(t) ? "Balanced" : "Not Balanced") << '\n';
+    string line;
+    // Read multiple lines until EOF
+    while (getline(cin, line)) {
+        bool balanced = areParenthesesBalanced(line);
+        cout << (balanced ? "Balanced" : "Not Balanced") << '\n';
     }
-    */
+
     return 0;
 }