poj 2136 Vertical Histogram

#include <iostream>
#include<string>
using namespace std;
int letter[27];
int main()
{
    string str;int i,j;
    for( i=0;i<4;i++)
    {
        getline(cin,str);
        for( j=0;j<str.size();j++)
            if(str[j]>=65&&str[j]<=90)
                letter[str[j]-64]++;
    }

    int max=0;
    for(i=1;i<=26;i++)
        if(letter[i]>max)max=letter[i];

    for( i=max;i>=1;i--)
    {
        for( j=1;j<=26;j++)
            if(letter[j]>=i)
                cout<<"* ";
            else 
                cout<<"  ";
        cout<<endl;
    }
    for( i=65;i<=90;i++)
        cout<<(char)i<<" ";
    cout<<endl;
    return 0;
}