Reading two line continuously using getline function in c++

Question

I was learning how to read strings with getline function.

I know that getline function read string as far as we don\'t hit enter or the size value in the getline para

Answer 1

std::istream::getline is being overloaded with data.

According to cppreference,

Behaves as UnformattedInputFunction. After constructing and checking the sentry object, extracts characters from *this and stores them in successive locations of the array whose first element is pointed to by s, until any of the following occurs (tested in the order shown):

• end of file condition occurs in the input sequence (in which case setstate(eofbit) is executed)
• the next available character c is the delimiter, as determined by Traits::eq(c, delim). The delimiter is extracted (unlike basic_istream::get()) and counted towards gcount(), but is not stored.
• count-1 characters have been extracted (in which case setstate(failbit) is executed).

Emphasis mine.

cin.getline(line1,7);
//                ^ This is count

can read only 6 characters with the 7th reserved for the null terminator. "oranges" is seven characters, and this places cin in a non-readable error state that must be cleared before reading can be continued. Reading of the second line

cin.getline(line2,7);

instantly fails and no data is read.

The obvious solution is

cin.getline(line1, sizeof(line1));

to take advantage of the whole array. But...

Any IO transaction should be tested for success, so

if (cin.getline(line1, sizeof(line1)))
{
    // continue gathering 
}
else
{
    // handle error
}

is a better option.

Better still would be to use std::getline and std::string to almost eliminate the size constraints.