getting input from user always falls short by 1

Question

I'm trying to get n lines of input (Strings) from the user

The n is set first
I initialize an array of Strings to save the input and for loop to save them.

The problem is that it always falls short meaning

if n=1 the program is terminated
if n=2 it takes only 1 input
if n=3 it takes only 2 inputs and so on ......

What is wrong ?

Scanner sc = new Scanner(System.in);
//how many lines should be taken
int lines = sc.nextInt(); 
// initialize input array
String[] longWords = new String[lines] ;

//set the input from the user into the array
for (int i = 0; i < longWords.length; i++) {
    longWords[i] = sc.nextLine() ;
}

score 3 · Accepted Answer · answered Aug 30 '14 at 15:31

Do it like this:

Scanner sc = new Scanner(System.in);
//how many lines should be taken
int lines = sc.nextInt(); 

//read the carret! This is, the line break entered by user when presses Enter
sc.nextLine();

// initialize input array
String[] longWords = new String[lines] ;

//set the input from the user into the array
for (int i = 0; i < longWords.length; i++) {
    longWords[i] = sc.nextLine() ;
}

score 0 · Answer 2 · answered Aug 30 '14 at 15:41

The issue is that nextInt() does not process the newline character at the end of a line of input, so when you enter 1 for instance, Scanner sees '1, '\n', but only takes in the '1'. Then when you call nextLine(), it sees the newline character left over and then immediately returns. It's a hard error to find, but just always remember whether or not the newline character is still waiting to be processed.

getting input from user always falls short by 1

2 Answers2