作业3（3）

#include<stdio.h>
int main(void)
{
int letter,blank,digit,other;/*定义整数型变量*/
char ch;
int i;
letter=blank=digit=other;
printf("Enter 15 characters:");
for(i=1;i<=15;i++){/*判断当i<=15时*/
ch=getchar();
if((ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z'))/*判断*/
letter++;
else if(ch>='0'&&ch<='9')
digit++;
else if((ch='\n')||(ch=' '))
blank++;
else
other++;

}
printf("letter=%d,digit=%d,blank=%d,other=%d\n",letter,digit,blank,other);
return 0;
}