Help with loop to convert string to int

[m712]

trying to a string variable named hexnumber to convert each character (a through f ) to corresponding integer (10-15):

int input[100];//array of ints to store user's input digits
	int i;
	char j='a',k='A';
	int u=10;//to convert a to 10 and increment when incrementing letters
	//converting lowercase letters their corresponding integer of type int
	while(j<='f')
	{
		i=0;
	for(i=0;i<=(hexnumber.size()-2);i++)
	{ 
		if(hexnumber[2+i]==j||hexnumber[2+i]==k)
		{input[i]=u;}
		
	   i++;
	}
	   u++;
	   j++;
	   k++;

	}
	
	cout<<input[0]<<input[1];

[master5001]

This is covered on the FAQ.

[m712]

But I'm not allowed to use any of that stuff (this is for school).

[master5001]

Here is a hint:

char input[] = "af";

toupper(input[0])-'A' = 0
toupper(input[1])-'A' = 5

[m712]

Thanks. I think the method that I used also works ( haven't checked it completly, though). I just noticed that there is an unecessary incrementation of the variable i in the for loop. The outupt is coming out like I expect it too now.