练习3-4
统计字符
#include<stdio.h>

int main()
{ int letter,blank,digit,other;
char ch;
int i;
letter=blank=digit=other=0;
for(i=1;i<=10;i++)
{ch= getchar();
if(ch>='A'&&ch<='z')
letter++;
else if(ch==' '||ch=='\n')
blank++;
else if(ch>='0'&&ch<='9')
digit++;
else
other++;
}
printf(" letter=%d blank=%d digit=%d other=%d",letter,blank,digit, other);
return 0;
}