Thread: what is charAt(0) ?

Is there anybody could tell me what does this function use for?For example :

String strTemp = JOptionPane.showInputDialog(null,"Please Enter C To Open A Current Account \n Or J To Open A Joint Account");
switch(strTemp.charAt(0)){
				case 'c':
				case 'C':
                              //code statement
                               break;
                              case 'j':
                              case 'J':
 }

Basically if i program the statement in c++ ,i would coding it in this form

switch(strTemp)
{
                               case 'c':
				case 'C':
                              //code statement
                               break;
                              case 'j':
                              case 'J':
 }

But it won't work in java ,while i try to compile it an error prompt out mentioned that ("invalid type" in switch(strTemp)) So why ?

Hello.

The reason for the switch statement not liking "strTemp" being passed in is because you cannot use switch for checking strings. However if you use strTemp.charAt(0) you will get the first character in the string, hence the index zero (0). We can then use the switch to check the character. Switch will take anything represented as a number of int or lower or an enum. So thats byte, short, int, char and enum.

// Json

I think you need to learn C++ better too before making those kind of remarks.

#include <string>
#include <iostream>
 
using namespace std;
 
int main(void){
    string test = "j";
 
    switch(test){
        case 'j':
            cout << "It worked! Huh... How!";
            break;
        default:
    }
 
    retrun 0;
}

this is an epic fail.

Not really

But here goes, in most cases in Java, the index is zero based. So for instance in the charAt method you will have to use a zero to get the first character. However if you wish to do a substring between x and y only the start position is zero based but the end is not. Not sure if that makes any sense, just have a look at the API reference.

// Json