Program is skipping over Getline() without taking user input [duplicate]

问题

This is a very strange problem, when my program asks the user for the address, instead of waiting for input, it seems to skip the getline() function completely

Answerinput:

cout << "would you like to add another entry to the archive? (Y/N):";

cin >> answer;

cout << endl;
cout << endl;

answer = toupper(answer);


 switch(answer)
    {
    case 'Y':
        Entrynumber++;

        cout << "began record number " << Entrynumber << "+ 1." << endl;

        cout << "Enter the last name of the person to be entered" << endl;

        cin >> stringentry;
        cout << endl;

        stringlength = stringentry.length();

        strcpy(Record[Entrynumber].Last_Name, stringentry.c_str());


        Record[Entrynumber].Last_Name[stringlength] = '*';



        cout << "Enter the first name of the person" << endl;

        cin >> stringentry;
        cout << endl;

        stringlength = stringentry.length();

        strcpy(Record[Entrynumber].First_Name, stringentry.c_str());

        Record[Entrynumber].First_Name[stringlength] = '*';

        cout << "Enter the SSN of the person" << endl;
        cin >> Record[Entrynumber].SSN;
        cout << endl;

        cout << "Enter the age of the person" << endl;
        cin >> Record[Entrynumber].Age;
        cout << endl;

        cout << "Enter the address of the person" << endl;


        cin.getline(Record[Entrynumber].Address,70);


        cout << endl;


        stringentry = Record[Entrynumber].Address;

        stringlength = stringentry.length();



        Record[Entrynumber].Address[stringlength] = '*';

        cout << "you entered:" << endl;



        for(jim = 0 ; Record[Entrynumber].Last_Name[jim + 1] != '*' ; jim++)
        {
            cout << Record[Entrynumber].Last_Name[jim];
        }

        cout << ',' ;


        for(jim = 0 ; Record[Entrynumber].First_Name[jim + 1] != '*' ; jim++)
        {
            cout << Record[Entrynumber].First_Name[jim];
        }

        cout << endl;

        cout << Record[Entrynumber].SSN << endl;
        cout << Record[Entrynumber].Age << endl;

        for(jim = 0 ; Record[Entrynumber].Address[jim + 1] != '*' ; jim++)
        {
            cout << Record[Entrynumber].Address[jim];
        }
        cout << endl;
        cout << endl;


        goto Answerinput;
    case 'N':
        cout << "ok" << endl;
        break;
    default:
        cout << "invalid answer" << endl;
        goto Answerinput;
    }

output to console

would you like to add another entry to
the archive? (Y/N):Y

began record number 6+ 1. 


 Enter the last name of the person to be entered 
 John


 Enter the first name of the person 
 John

 Enter the SSN of the person  22222222

 Enter the age of the person  22

 Enter the address of the person

 you entered: 
Joh,Joh 
22222222 
22
 *¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦
 //////////////22 more lines of'|'//////////////////////////////////////////////
 ... 
¦¦¦¦¦¦¦¦l3-j

 would you like to add another entry to the archive? (Y/N):

Both cin.getline() and getline() do the same thing.

I'm using MVC++ 2008.

All of the fields in the Record array are structs, Record[Entrynumber].Address is a char array.

回答1:

Cin is probably leaving the carriage return in the buffer which getline retrieves. Try

cin.ignore(1000, '\n');

cin.getline(Record[Entrynumber].Address,70);

The >> operator doesn't remove the newline character after retrieving data, but ignores leading whitespace before retrieving data, while getline just retrieves whatever is in there, and removes the '\n' after reading as it is apart of the line it is 'getting'.

回答2:

Seeing as how there might be input left over in the buffer which your getline is reading first, I'd suggest you clear the buffer before trying to input the next data:

std::cin.ignore(std::numeric_limits<std::streamsize>::max(),'\n');

来源：https://stackoverflow.com/questions/3731529/program-is-skipping-over-getline-without-taking-user-input

标签

c++

iostream

getline