#include<iostream>
using namespace std;
int main()
{
    int letter=0,digit=0,space=0,other=0;   
    int i;
    char *p,string[20];
    void search(char *p,char string[]);

    cout<<"input string:"<<endl;
    while((string[i]=getchar())!='\n')
    i++;

    search(p,string);
    cout<<"letter="<<letter<<endl<<"space="<<space<<endl<<"digit="<<digit<<endl<<"other="<<other<<endl;
   
    return 0;
}
void search (char *p,char string[])
{
    int letter=0,digit=0,space=0,other=0;
      p=&string[0];
    while(*p!='\n')
    {
        if(('a'<=*p)&&(*p<='z')&&('A'<=*p)&&(*p<='z'))
           ++letter;
        else if(*p==' ')
            ++space;
        else if((*p<='9')&&(*p>='0'))

            ++digit;
        else
            ++other;
        p++;
    }

}

Thank you, may I say is too depression of the mouth

,Thank you

谢谢了，呵呵