HDU 2716 Water problem

Very water topic, depressed is my topic to see wrong

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

int key[26];

void Inti (char ch[])
{
	int i;
	for (i=0;i<26;i++)
	{
		key[i]= ' a ' +i;
	}
	int Len=strlen (CH);
	for (i=0;i<len;i++)
	{
		if (ch[i]>= ' a ' &&ch[i]<= ' Z ') ch[i]=ch[i]-' a ' + ' a ';
		key[i]=ch[i]-key[i];//number of differences
	}
	while (i<26)
	{
		key[i]=0;
		i++;
	}
}

int main ()
{
	char ch[100];
	while (gets (CH))
	{
		Inti (CH);
		Gets (CH);
		int I,len=strlen (CH);
		for (i=0;i<len;i++)
		{
			if (ch[i]== ')
			{
				printf ("");
				Continue;
			}
			if (ch[i]>= ' a ' &&ch[i]<= ' z ')
				printf ("%c", ch[i]+key[ch[i]-' a ']);
			else
				printf ("%c", ch[i]+key[ch[i]-' A ']);
		}
		Putchar (' \ n ');
	}
	return 0;
}