Infinite while loop

[madafaka]

guys i am this term i am taking basic c++ course and in this homework, i encountered an infinite loop problem and i dont know how to fix it. i am pretty sure that it is an easy problem for you, so if you help, i will appreciate it. so here is the problem;

in here i have to make an input check to see that if the user enters a string longer than 39 characters.

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

int main()
{
string scrambledText;

cout << "Scrambled Text: ";
cin >> scrambledText;

int i = scrambledText.length();

if (i < 40)
{
while (i < 40)
{
cout << "Input string must be longer than 40 characters" << endl ;
}
}
return 0;
}

but when i run the program it keeps writing "Input string must be longer than 40 characters". so i dont want it obviously :) what i want is, to go to the beginning and let the user input anoter string again. i really need your help. thx

[akdemirc]

have a look at do-while loop, it is more convenient in your case, simply force user to input as long as it has a length < 40

do
{
cout << "Scrambled Text: ";
cin >> scrambledText;

}while (scrambledText.length < 40);

// here you will get scrambledText.length > 40

[madafaka]

it worked :) thank you so much