Thou shalt not put queries in for loops (Bad example)

gistfile1.txt

List<Account> accList = new List<Account>([Select Id,Name From Account]);

for(Account acc : accList){
    Integer numWithEmail = 0;
    for(Contact cont : [Select Id,Email From Contact Where AccountId = :acc.Id]){
        if(!String.isEmpty(cont.Email)){
            numWithEmail++;
        }
    }
}