the length of the string.txt

求面积

#include<stdio.h>
void main()
{int length(char *p);
 int len;
 char str[20];
 printf("input string: ");
 scanf("%s",str);
 len=length(str);
 printf("The length of string is %d.\n",len);
}
 int length(char *p)
 {int n;
  n=0;
  while(*p!='\0')
   {n++;
    p++;
  }
return(n);
}