reading lines

[kmtompkins]

i would like to read multiple line like if i input "test1 test2"
it outputs test1 test2
not just test1
i used getline()
but it only reads the first space and after

#include <iostream>
#include <string>

using namespace std;

int main()
{
	string code;
	string message;
	
	cout << "encode or decode: ";
	cin >> code;

	if (code == "encode")
	{
		cout << "Input the message would u like to encode" << endl;
		cin >> message;
		getline(cin, message);
		cout << message << endl;
	}
	return 0;
}

[long double main]

cout << "Input the message you would like to encode:" << endl;
getline(cin >> ws, message);
cout << message << endl;

What happens is that cin >> something; leaves a newline in the input buffer (from you pressing Enter), but getline stops as soon as it sees a newline character, so if you call getline after doing a cin >> something, then your getline won't get anything, which is why we need the cin >> ws part to clear out all leading whitespace before getting the input.

[kmtompkins]

it still only reads the end part i input "test1 test2"
it outputs "test2"

[long double main]

Did you delete the other cin >> message;?

[kmtompkins]

ok i got it thanks also do u know how i can read the leters of message and replace them with other letters such as...

a=n
b=o
c=p
d=q
e=r
f=s
g=t
h=u
i=v
j=w
k=x
l=y
m=z

[kmtompkins]

so if i put in "hi how are you"
it outputs
"uv ubj ner lbh"

[Disch]

You are mixing >> with getline.

>> will stop as soon as it finds whitespace following non-whitespace. Any leading whitespace is discarded, and trailing whitespace is left in the buffer.

Example... if the user inputs [space][space]foo[newline]
Then:
- the first 2 spaces are discarded
- the >> operator will extract "foo" (with no spaces)
- the newline remains inside the cin buffer.



On the other hand.. getline() extracts the entire line up to the next newline character. Whitespace is preserved... and the trailing newline is discarded.

Example... if the user inputs the same thing: [space][space]foo[newline]
- getline extracts "[space][space]foo"
- the newline is discarded
- cin buffer is empty



With that out of the way.... let's look at your program:

// line 12:
cin >> code;

// user inputs:  "encode\n"  (\n is the newline when they press enter)
//  result... code=="encode", cin buffer has "\n" in it


// line 17:
cin >> message;

// user inputs "test1 test2\n"
// cin buffer now has "\ntest1 test2\n"
//  result... message="test1"
//     leading \n is discarded
//     cin buffer has " test2\n" still in it

// line 18:
getline(cin, message);

// user has no chance to input anything, as cin buffer is not empty
// cin buffer still contains " test2\n"
// result...  message=" test2"
//   trailing \n is discarded
//   cin buffer is now empty 

The solution

When you need to have >> followed by a getline... put a cin.ignore between them. cin.ignore will discard any lingering newlines in the buffer that the >> operator left there.

EDIT:

Man did I get ninja'd like 4 times?

EDIT 2:

long double main wrote:

which is why we need the cin >> ws

!! That's neat! I never knew about that!