I am trying to read user entered data from the stream and then store it in a custom String class.

To my best knowledge, std::getline() can route data only to std::string , that is why I need to come up with something else, as my project is not allowed to use std::string class.

My code looks like this:

String street();
std::cout << "Street: "; std::cin >> std::noskipws;
char c='\0';
while(c!='\n'){
    std::cin >> c;
    street=street c;
}std::cin >> std::skipws;
    
int bal=0;
std::cout << "Balance: "; std::cin >> bal;

CodePudding user response：

You can use the C function "getchar()" to read a single character from standard input. This link describes it: https://www.ibm.com/docs/en/i/7.3?topic=functions-getc-getchar-read-character.

Here is my code:

String street=();
std::cout << "Street: ";
char c='\0';
while(c!='\n'){
    c = getchar();
    street=street c;
}

int bal=0;
std::cout << "Balance: "; std::cin >> bal;
cout << street << endl;

I hope this will help you, and I recommend you make an independent function that will read line from standard input and whose return type will be "String". You can declare it as:

String readLine();

And I also recommend you to pay attention to that while loop because string that is obtained from that loop will have character '\n' at the end of it.

CodePudding user response：

To my best knowledge, std::getline() can route data only to std::string , that is why I need to come up with something else, as my project is not allowed to use std::string class.

Note that std::getline and std::istream::getline are two separate functions. The former will work with std::string while the latter will work with C-style strings (i.e. sequences of characters that are terminated by a null character).

Therefore, if you are not allowed to use std::string, then you can still use std::istream::getline, for example like this:

char line[200];
String street;

std::cout << "Street: ";

if ( std::cin.getline( line, sizeof line ) )
{
    //the array "line" now contains the input, and can be assigned
    //to the custom String class
    street = line;
}
else
{
    //handle the error
}

This code assumes that your custom class String has defined the copy assignment operator for C-style strings.

If it is possible that the lines will be larger than a fixed number of characters and you want to support such lines, then you could also call std::istream::getline in a loop:

char line[200];
String street;

std::cout << "Street: ";

for (;;)
{
    std::cin.getline( line, sizeof line );

    street  = line;

    if ( std::cin.bad() )
    {
        //TODO: handle error
    }

    if ( !std::cin.fail() || std::cin.eof() )
        break;

    std::cin.clear();
}

This code assumes that operator = is defined for class String.

This loop will continue forever until

1. getline succeeds (i.e. it is able to extract (but not store) the newline character), or

2. end-of-file is reached (eofbit is set), or

3. an error occurs (badbit is set).