这时一个计算字符串中字母，数字，空格个数的程序。
#include<stdio.h>
#include<string.h>
void main()
{
    char s;

    int letter=0,space=0,number=0,others=0;
    printf("please input\n");

    while(（s=getchar（））!='\n')
    {
            if((s>='a'&&s<='z')||(s>='A'&&s<='Z'))
            
                letter++;
            
                else if(s>='0'&&s<='9')
               
                    number++;
               
                    else if(s==' ')
                        space++;
                        else
                        others++;
               
        
    }    printf("letter=%d,number=%d,space=%d,others=%d\n",letter,number,space,others);
}
但经过实验，若是有scanf输入字符串，程序没错误但也没有响应。用gets会有错误。用getchar正确。求解为什么？多谢啊