Java Reference
In-Depth Information
To read the ID we use the method nextInt ; to read the name we use the method
nextLine . Notice that after reading the ID , the reading marker is after the ID and the
character after the ID is the newline character. Therefore, after reading the ID , the
reading marker is after the ID and at the newline character (of the line containing the ID ).
The method nextLine reads until the end of the line. Therefore, if we read the name
immediately after reading the ID , then the method nextLine will position the reading
marker after the newline character following the ID , and nothing will be stored in the
variable name . Because the reading marker is just before the name, if we use the method
nextInt to read the voting data, the program will terminate with an error message.
Therefore, it follows that to read the name, we must discard the newline character after
the ID , which we can do using the method nextLine . (Assume that discard is a
variable of type String .) Therefore, the statements to read the ID and name are as
follows:
ID = inFile.nextInt(); //read the ID
discard = inFile.nextLine(); //discard the newline character
//after the ID
name = inFile.nextLine(); //read the name
The general loop to process the data is:
5
while (inFile.hasNext())
//Line 1
{
//Line 2
ID = inFile.nextInt();
//Line 3
discard = inFile.nextLine();
//Line 4
name = inFile.nextLine();
//Line 5
//process the numbers in each line
}
The code to read and sum up the voting data uses a while loop as follows:
sum = 0;
//Line 6
num = inFile.nextInt();
//Line 7; read the first number
while (num != -999)
//Line 8
{
//Line 9
sum = sum + num;
//Line 10; update sum
num = inFile.nextInt();
//Line 11; read the next number
}
//Line 12
We can now write the following nested loop to process the data:
while (inFile.hasNext())
//Line 1
{
//Line 2
ID = inFile.nextInt();
//Line 3
discard = inFile.nextLine();
//Line 4
name = inFile.nextLine();
//Line 5
sum = 0;
//Line 6
num = inFile.nextInt();
//Line 7; read the first number
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