#include <stdio.h>
#include <string.h>
void main()
{
    int  i,j,b[4]={0,0,0,0},t;
    char a[50];

    printf ("请输入一个字符串：\n");
    gets(a);
    t=strlen(a) ;
   
    if (t==0)
   
        printf ( "这是一个空字符串!\n" ) ;
    else
        {
            for (i=0;i<=t;i++)
            {
                if (a[i]>='0'&&a[i]<='9')
                    b[0]++;
                else if (a[i]==' ')
                    b[1]++;
                else if (a[i]>='A'&&a[i]<='Z')
                    b[2]++;
                else if (a[i]>='a'&&a[i]<='z')
                    b[2]++;
                else
                    b[3]++;
            }
        
            for (j=0;j<=3;j++)
                printf("b[%d]=%d\n",j,b[j]);
        }
    printf("字符串长度是：%d\n",t);
}
为什么b[3]比字符串长度多1

谢了，我知道了