float 有点晕

pspwd

void main()
{
  float price = 525.75;
   float sales_tax = 0.06;

   printf("The item cost is %f\n", price);

   float result;
   result=price * sales_tax;
   printf("Sales tax on the item is %f\n",result );

}

The item cost is 525.750000
Sales tax on the item is 31.545000

void main()
{

   float price = 525.75;
   float sales_tax = 0.06;

   printf("The item cost is %f\n", price);

   float result;

   printf("Sales tax on the item is %f\n",price * sales_tax );

}
The item cost is 525.750000
Sales tax on the item is 31.544999

kj501

浮点数是不能精确表示的，运算过程会有误差。估计前一个程序是在将运算结果赋值给浮点变量result时，可能在截断尾数时进行了舍入。