Validating keyboard input data

Question

I am new to java and have a question regarding validating input.
I did check the FAQ for "Validating keyboard input data" but found no help.
I have to check that the keyboard input is only one of the following char a c,C,d,D
Ihave tried different conditional loops and statements but cannot get it right.
Could someone point me in the right direction.
I am using the latest java.
Thanx

Answer 1

well i think i am close but i can't figure out why i have an endless loop or how to fix it
System.out.print("Please enter the Costumer Type C or R: ");
String cosTypeTemp = scan.nextLine();
cosType = cosTypeTemp.charAt(0);
while (cosType != 'c' || cosType != 'C' || cosType != 'd' || cosType != 'D');
do
costumerType = 'N';
System.out.print("Wrong input please enter the Costumer Type c or r: ");
cosTypeTemp = scan.nextLine();
cosType = cosTypeTemp.charAt(0);
while (cosType != 'c' || cosType != 'C' || cosType != 'd' || cosType != 'D');
costumerType = cosType;
System.out.print("Please enter the Number of basic service connections: ");
System.out.print("Please enter the Costumer Type C or R: ");
String cosTypeTemp = scan.nextLine();
cosType = cosTypeTemp.charAt(0);
while (cosType != 'c' || cosType != 'C' || cosType != 'd' || cosType != 'D');
do
costumerType = 'N';
System.out.print("Wrong input please enter the Costumer Type c or r: ");
cosTypeTemp = scan.nextLine();
cosType = cosTypeTemp.charAt(0);
while (cosType != 'c' || cosType != 'C' || cosType != 'd' || cosType != 'D');
costumerType = cosType;
System.out.print("Please enter the Number of basic service connections: ");
numBsSrvConecs = scan.nextInt();
when i enter the correct data ( c, C, d, D) it goes into infinite loop and never reaches the next keyboard scan for System.out.print("Please enter the Costumer Type C or R: ");