QT day 1

#include 
 
using namespace std;
 
int main()
{
    cout << "please enter str :";
    string str;
    getline(cin,str);
    int sum=0;
    int sum1=0;
    int sum2=0;
    int sum3=0;
    int sum4=0;
    for(unsigned long long i=0; i < str.size() ; i++)
    {
        if(str.at(i) >= 'A' && str.at(i) <='Z')
            sum++;
        else if(str.at(i) >= 'a' && str.at(i) <= 'z')
            sum1++;
        else if(str.at(i) == ' ')
            sum2++;
        else if( str.at(i) >= '0' && str.at(i) <='9' )
            sum3++;
        else
            sum4++;
 
    }
 
    cout <<  "大写字母有" << sum << endl;
    cout <<  "小写字母有" << sum1 << endl;
    cout <<  "空格有" << sum2 << endl;
    cout << "数字有" << sum3 << endl;
    cout <<  "其他字符有" << sum4 << endl;
    return 0;
}