运行一个程序出了点错误 求改改

#include<stdio.h>
int main()
{int i,j,upp,low,dig,spa,oth;
char text[3][80];
upp=low=dig=spa=oth=0;
for (i=0;i<3;i++)
{printf("piease input line %d:\n",i+1);
gets(text[i]);
for (j=0;j<80 && text[i][j]!='\0';j++)
{if (text[i][j]>='A' && text[i][j]<='Z')
upp++;
else if (text[i][j]>='a' && text[i][j]<='z')
low++;
else if (text[i][j]>='0' && text[i][j]<='9')
dig++;
 else if (text[i][j]=='')
 spa++;
else
 oth++;
}
}
printf("\nupper case:%d\n",upp);
printf("lower case %d\n",low);
printf("digit   :%d\n",dig);
printf("space   :%d\n",spa);
printf("other   :%d\n",oth);
return 0;
}