my problem in c++

#include<iostream.h>main(){	char a;	int i=0;	cout<<"Enter a number or a letter\n";	cin>>a;	for (i='0';i<'10';i++)	{	    if (a=i)		{			cout<<"you printed a number...\n";		}		break;	}   	for (i='A';i<'Z';i++)	{	    if (a=i)		{			cout<<"you printed a capital letter...\n";		}		break;	}	for (i='a';i<'z';i++)	{		if (a=i)		{			cout<<"you printed a letter...\n";		}		break;	}	return 0;}