size of

 char s1[]="";
 char s2[]="Hello world!";
 char *p = s2;
 char *q = s1;
 char *r = (char *)malloc(100);
 char str1[]="123456789";
 char *a[]={"123","asdfsdf","0kle3340j"};
 
 char s3[10]={'m','o','b','i','l'};
 char s4[20]={'A','N','S','I','/0','C','+','+'};
 char s5[8]={'I','S','O','C','+','+','M'};

 int i;
 int j = 10;
 float f;
 float k=12.45;
 long l;
 double d;

void func(char str[100])
{
 printf("sizeof---str=%d/n",sizeof(str));
}

int tenof(char par)
{
 return par*10;
}

func(str);

printf("tenof(100)=%d",tenof(100));
printf("tenof(127)=%d",tenof(127));
printf("tenof(128)=%d",tenof(128));
printf("tenof('i')=%d",tenof('i'));

=========================================

sizeof(s1)=1
sizeof(s2)=13
sizeof(p)=4          //s2的首地址值的字节数是4位
sizeof(q)=4
sizeof(r)=4
sizeof(str)=4

strlen(s3)=5
strlen(s4)=4
strlen(s5)=7

sizeof(i)=4          //int型变量的地址字节数是4位
sizeof(j)=4
sizeof(f)=4
sizeof(k)=4
sizeof(l)=4
sizeof(d)=8          //double型变量的地址字节数是8位

sizeof(a)=12
sizeof(a[0])=4
sizeof(a[1])=4
sizeof(a[2])=4

sizeof---str=4
tenof(100)=1000
tenof(127)=1270
tenof(128)=-1280    //ASCII 编码只有 000~127 是标准的
tenof('i')=1050