提示并输入一个字符串，统计该字符串中字母个数、数字个数、空格个数、其他字符的个数

#include <iostream>

using namespace std;

int main()
{
    cout<<"请输入字符串:";
    string str;
    getline(cin,str);
    int num=0;
    int alp=0;
    int spa=0;
    int other=0;
    int len=str.length();
    for(int i=0;i<len;i++)
    {
        if(str[i]>='0'&&str[i]<='9')
        {
            num++;
        }else if((str[i]>='a' && str[i]<='z')||(str[i]>='A' && str[i]<='Z'))
        {
            alp++;
        }else if(str[i]==' ')
        {
            spa++;
        }else
        {
            other++;
        }
    }
    cout<<"数字"<<num<<"个"<<endl;
    cout<<"字母"<<alp<<"个"<<endl;
    cout<<"空格"<<spa<<"个"<<endl;
    cout<<"其他字符"<<other<<"个"<<endl;
    return 0;
}