C++ Qt day1

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提示并输入一个字符串，统计该字符中大写、小写字母个数、数字个数、空格个数以及其他字符个数(要求使用C++风格字符串完成)

#include <iostream>
#include <string.h>
#include <array>
using namespace std;

int main()
{
    string str;
    cout << "请输入字符串:";
    getline(cin,str);
    int i=0;
    int capital=0,lowercase=0,number=0,space=0,other=0;
    while(str[i]!='\0')
    {
        if(str[i]>='A' && str[i]<='Z')
        {
            capital++;
        }
        else if(str[i]>='a' && str[i]<='z')
        {
            lowercase++;
        }
        else if(str[i]>='0' && str[i]<='9')
        {
            number++;
        }
        else if(str[i]==' ')
        {
            space++;
        }
        else
        {
            other++;
        }
        i++;
    }
    cout << "大写字母个数：" << capital << endl;
    cout << "小写字母个数：" << lowercase << endl;
    cout << "数字个数：" << number << endl;
    cout << "空格个数：" << space << endl;
    cout << "其他字符：" << other << endl;
    return 0;
}