Why Doesn\'t `getline` Prompt for Input After Using `cin`?

getline Not Prompting for Input

In your code, when you call getline(cin, mystr);, the program fails to prompt the user for input. This is because when you previously used cin >> name; and cin >> i;, the newline character that the user entered after typing their response was left in the input buffer.

Whitespace Delimitation

The >> operator is whitespace delimited. This means that when the user presses the Enter key after entering data, the newline character is not stored in the variable but remains in the input buffer.

getline's Behavior

getline is also whitespace delimited. When you call getline, it searches the input buffer for a newline character. Since the newline character is already present in the buffer, getline finds what it's looking for immediately and does not prompt the user for input.

Solution

To fix this issue, you can use one of the following methods:

1. Call ignore: Between using >> and getline, call cin.ignore() to clear the newline character from the input buffer.
2. Use getline Exclusively: Instead of using >>, use getline for all user input. Use stringstream to convert the string input to the desired data type.

Improved Code:

Here's an improved version of your code that uses getline exclusively:

#include <iostream>
#include <string>
#include <sstream>

using namespace std;

int main() {
    string name;
    int age;
    float price;

    cout << "Hello World!" << endl;
    cout << "What is your name? ";
    getline(cin, name);
    cout << "Hello " << name << endl;
    cout << "How old are you? ";
    getline(cin, age);
    cout << "Wow " << age << endl;

    cout << "How much is that jacket? ";
    getline(cin, price);
    stringstream(price) >> price;
    cout << price << endl;
    system("pause");

    return 0;
}

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