📅 Date: Jan 27, 2026
🔥 Topic: String Input Issues (getline) & Mutable Logic

🚫 The Bug with 'cin'

I encountered a major issue today. I tried to input my full name "Sahil Tiwari" using cin.

Result: It only stored "Sahil".
Reason: cin stops reading as soon as it sees a SPACE or Enter.

✅ The Solution: getline()

To read a whole line (including spaces), we use the getline() function. 

string fullName;
getline(cin, fullName); // Reads entire line

🧠 Mutable vs Immutable

In some languages (like Java/Python), strings are Immutable (cannot be changed once created).
Good News: In C++, Strings are Mutable. I can change any character directly. 

string s = "Hello";
s[0] = 'J'; 
// s becomes "Jello". Easy!

💻 Day 27 Code: Input Fix

#include <iostream>
#include <string>
using namespace std;

int main() {
    string sentence;

    cout << "Enter a sentence: ";
    
    // cin >> sentence; // This would FAIL on spaces
    getline(cin, sentence); // This WORKS

    cout << "You typed: " << sentence << endl;

    return 0;
}

💭 Thoughts

Using getline is essential for competitive programming when input formats are tricky. This marks the end of my String basics. Tomorrow, I start solving classic logic problems!