c错误local variable string used without having been initializ

#include<stdio.h>
void strlenth(char *p);
int main(void)
{
char *pstr;
int len=0;
char string;
printf(“please input a sentence:”);
scanf(“%s”,string);
pstr=&string;
strlenth(pstr);
printf(“%d\n”,len);
return 0;
}
void strlenth(char *p)
{
char A;
int len=0;
p=&A;
if (p!=””\0″”)
len++,p++;
}