CareerCup

Implementing a hexdec counter.
Assumption: Max value is FFFFFFFFF The counter will reset when it reaches this max value.

char IncrementChar(char ch)
{
	switch (ch)
	{
	case '0':
	case '1':
	case '2':
	case '3':
	case '4':
	case '5':
	case '6':
	case '7':
	case '8':
		return (char) ((int) ch + 1);
		break;
	case '9':
		return 'A';
                break;
	case 'A':
	case 'B':
	case 'C':
	case 'D':
	case 'E':
		return (char) ((int) ch + 1);
		break;
	case 'F':
		return '0';
		break;
	default:
		return ' ';
		break;
	}	
}

char* IncrementString (char *str)
{
	if( !strcmp(str,"FFFFFFFFF"))
		return "000000000"; // Reset the counter after it reaches max

	for (int i=8; i>=0;i--)
	{
		str[i] = IncrementChar(str[i]);
		if ( str[i] != '0') 
			return str;
	}
	return str;
}

int _tmain(int argc, _TCHAR* argv[])
{

	char num[10] = "000000000";
        // Print value till FFF
	while(strcmp(num,"000000FFF") != 0)
	printf("%s\n" , IncrementString(num));
	return 0;
}

Is it hexadecimal ?. If it isnt then the max value of counter be ZZ9ZZ9999

The given string contains Hex values hence convert it to Decimal values fist then increment the value again convert it back to Hex. You will get the answer. Simple.

create a map from single "digit" n to n+1
increase the tail digit, if overflow, recursively increase the previous digit.
The solution can handle unlimited length strings.
js code:

var map = {
    0: "1",
    1: "2",
    ...
    C: "D",
    D: "0"
}
function increase(str) {
	var array = [];
	for(var i=str.length-1; i >= 0;i--){
		array.push(str.charAt(i));
	}
	array = increaseAt(array, 0);
	
    return  array.reverse().join("");
}

function increaseAt(array, index) {
	var d = array[index];
	var next = map[d];
	array[index] = next;
	
	if(next === "0") {// overflow
		var nextIndex = index+1;
		if(nextIndex  >= array.length) {
			array.push("1");
		} else {
			array = increaseAt(array, nextIndex);
		}
	}
	return array;
}

Very ambigious question . Please provide with proper requirements

public static String couterString(String s, int length){
char[] schar = s.toCharArray();
char c = schar[length-1];
if(c == '9'){
c = 'A';
schar[length -1] = c;
return String.valueOf(schar,0,length);
}else if(c == 'F'){
c= '0';
return couterString(s, length-1) + String.valueOf(c);
}else{
c++;
schar[length -1] = c;
return String.valueOf(schar,0,length);
}
}

assuming that character values will be unchanged, i.e. max value will be AB9CD9999

public class StringCounter {

	public static void main(String[]args)
	{
		String input = "AB0CD00000", tmp ="", result="";
		
		int number = 0;
		
		for(int i=0;i<input.length();i++)
		{
			if(Character.isDigit(input.charAt(i)))
			{
				tmp+=Character.toString(input.charAt(i));
			}
		}
		
		tmp ="1"+tmp;
		
		number = Integer.parseInt(tmp);
		
		
		if(number+1<2*Math.pow(10, tmp.length()-1))
			number++;
		
		tmp = Integer.toString(number);
		
		int j= 1;
		
		for(int i=0;i<input.length();i++)
		{
			if(Character.isDigit(input.charAt(i)))
			{
				result+= tmp.charAt(j);
				j++;
			}
			else
			{
				result+= input.charAt(i);
			}
		}
		
		System.out.println(result);
	}
}

public partial class Form1 : Form
{
ArrayList arr = null;
string sv = string.Empty;
public Form1()
{
InitializeComponent();
sv = "AB0CD1010";
int iv = sv.Length;
arr = new ArrayList();
foreach (char ch in sv)
{
arr.Add(ch);
}
}

private void button1_Click(object sender, EventArgs e)
{
int inum = 0;
bool bOnce = false;
for(int i=0;i<=arr.Count-1;i++)
{
bool bNum = int.TryParse(arr[i].ToString(), out inum);
if (bNum)
{
int iFirst=0;
bool bFirst = int.TryParse(arr[i - 1].ToString(), out iFirst);
if (bFirst && !bOnce)
{
int ival = Convert.ToInt32(arr[arr.Count - 1].ToString());
int Inc = ival + 1;
arr[arr.Count - 1] = Inc.ToString();
bOnce = true;
}
}
textBox1.Text += arr[i].ToString();
}
textBox1.Text += "\r\n";
}
}

char[] incrementString(char str[])
{
    int index = lengthOf(str)-1;
	str[index]++;
	while((str[index]==58 || str[index]==91) && index>=0) //58 is ASCII_9 + 1, 91 is ASCII_Z + 1
	{
		if(str[index] == 58) //If 1 is added to 9
		{
			str[index] = 65; // Set it to A
			return str;
		}
		if(str[index] == 91) //If 1 is added to Z
		{
			str[index] = 48; // Set it to 0
			if(index == 0)
			{
				char incStr[lengthOf(str)+1];
				incStr = concatenateCharToArray('1', str); //Its trivial to write this function. It shall be omitted. For example if str is ABC234 All it does is retrun 1ABC234
				return incStr;
			}
			else
				str[--index]++;
		}

	}
}

I think the poster should clarify whether he has hex or is it like the one I am taking about in the above code snippet

#include<string>
#include<iostream>
using namespace std;

int increment(int i)
{

if(i=='f')
return 0;
else
return (i+1);

}
int main()
{

string a;

int i=0,j;
cout<< "enter the string"<<endl;
cin>>a;

int k=a.length();

while(i<k)
{


j=increment((int)a[k-i-1]);

a[k-i-1]=(char)(j);
if(j==0)
{
a[k-i-1]=(char)48;
i++;
}
else break;
}
cout<<a<<endl;
return 0;
}

void Increment(string &s)
{
	if(s.size()==0)
		return;
	int n=s.size()-1;

	for(int i=n;i>=0;i--)
	{
		if(s[i]-'0'>=0 && s[i]-'0'<=8)
		{
			s[i]=((s[i]-'0')+1)+'0';
			break;
		}
		else if(s[i]=='9')
		{
			s[i]='A';
			break;
		}
		else if(s[i]>='A' && s[i]<='E')
		{
			s[i]++;
			break;
		}
		else if(s[i]=='F')
		{
			s[i]='0';
			if(i==0)
			{				
				s='F'+s;
			}
		}
	}
}

int main()
{
	string s="0";//"AB0CD1010";

	for(int i=0;i<300;i++)
	{
		Increment(s);
		cout<<s<<endl;
	}

	return 1;

Number(parseInt("AB0CD1010",16)+1).toString(16)

Number(parseInt("AB0CD1010",16)+1).toString(16)

Number(parseInt("AB0CD1010",16)+1).toString(16)