Using std::getline() to read a single line? - c++

Question

My goal is to prompt user to enter a message / sentence and then print it out on the screen, using getline(). The following is two different attempts I have tried out.
First Attempt:
#include <iostream>
#include <iomanip>
#include <cstring>
using namespace std;
int main(){
chat message[80];
cout << "\n what is your message today?" << endl;
cin.getline( message, 80); // Enter a line with a max of 79 characters.
if( strlen( message) > 0) // If string length is longer than 0.
{
for( int i=0; message[i] != '\0'; ++i)
cout << message[i] << ' ';
cout << endl;
}
}
Second Attempt:
#include <iostream>
#include <iomanip>
#include <cstring>
using namespace std;
int main(){
string a = "a string";
cout << "\n what is your message today?" << endl;
while(getline(cin,a))
cout << a;
cout<<endl
}
}
For the fist attempt, the code simply print out "what is your message today?" and quit. I do not have a chance to enter any string at all. For the second attempt, it keeps asking me enter the message. Each time, when I enter something with the "\n", it would display what I entered on the screen. I use control + c to interrupt the running process to make it stop.
EDIT: To clarify and explain on my side, I extract the first attempt from a longer code, which is as the following.
#include <iostream>
#include <iomanip>
#include <cstring>
using namespace std;
char header[] = "\n *** C Strings ***\n\n"; // define a c string
int main()
{
char hello[30] = "Hello ", name[20], message[80]; // define a c string hello, declare two other c strings name and message
string a="fivelength";
cout << header << "Your first name: ";
cin >> setw(20) >> name; // Enter a word.
strcat( hello, name); // Append the name.
cout << hello << endl;
cin.sync(); // No previous input.
cout << "\nWhat is the message for today?"
<< endl;
cin.getline( message, 80); // Enter a line with a max of 79 characters.
if( strlen( message) > 0) // If string length is longer than 0.
{
for( int i=0; message[i] != '\0'; ++i)
cout << message[i] << ' ';
cout << endl;
}
return 0;
}
For the above code, it does not give me a chance to enter a message on the screen. I will put it as another question.

Answer 1

You are overcomplicating this, you can simply use std::string, which is the de-facto C++ string, and call the method, without using a loop.
You don't need a loop, since you are not going to repeatedly read lines, but only want to read one line, so no loop is needed.
#include <iostream>
#include <string> // not cstring, which is the C string library
using namespace std;
int main(void)
{
string message; // it can be an empty string, no need to initialize it
cout << "What is your message today?" << endl;
getline(cin, message);
cout << message;
cout<<endl;
return 0;
}
Output (Input: "Hello Stack Overflow!"):
What is your message today?
Message: Hello Stack Overflow!
PS: As #fredLarson commented, if you change chat to char in your first example, it should work. However, that code has a lot of commonalities with C.