C语言程序问题，谢谢各位

Question

在VS中运行以下程序，在除法部分结果出错了，请各位大神指导下，谢谢。

#include
#include
#include
#define DENSITY 62.4
int main(void)
{double weight,volume;
int size,letters;
char name[45];
printf("Hi!What's your first name?\n");
scanf("%s",name);
printf("%s,what's your weight in pounds?\n",name);
scanf("%f",&weight);
size=sizeof name;
letters=strlen(name);
volume=weight/DENSITY;
printf("Well,%s,your volumn is %2.2f cubic feet.\n",name,volume);
printf("Also,your first name has %d letters,\n",letters);
printf("and we have %d bytes to store it.\n",size);
system("pause");
return 0;

}

结果
volumn的结果是-14833270029408700000000000000000000000000

但在VC中运行结果为2.72，这是正确的。

Answer 1

改成 scanf("%lf",&weight); 就对了。
因为 单精度和双精度数据都是存的二进制，位数也不一样，当你将一个double双进度数据读成一个float单精度数据，
系统会截取部分数据去填充。