一個菜鳥關(guān)于c語言的初級問題

坐在地平線

#include <stdio.h>

int main(void)
{
  double pay = 0.0;                /* Weekly pay in dollars */
  double hours = 0.0;              /* hours worked          */
  int dollars = 0;                 /* Hourly rate - dollars */
  int cents = 0;                   /* ... and cents         */

  /* Get the Weekly pay */
  printf("Enter your weekly pay in dollars: ");
  scanf("%lf", &pay);

  /* Get the order quantity */
  printf("Enter the hours worked: ");
  scanf("%lf", &hours);

  /* Calculate the average hourly rate - dollars first */
  dollars = (int)(pay/hours);

  /* to get the cents we can subtract the dollars from the hourly rate           */
  /* and multiply by 100 to get cents. If we then add 0.5 and convert the result */
  /* back to an integer, it will be to the nearest cent.                         */
  cents = (int)(100.0*(pay/hours - dollars) +0.5);

  /* Output the average hourly rate */
  printf("Your average hourly pay rate is %d dollars and %d cents.\n", dollars, cents);
  return 0;
}
我想問一下，為什么要加上0.5呢？是不是涉及到精度的問題？先謝謝了

windy2335

100.0*(pay/hours - dollars)  是一個浮點型 ，如果直接強制轉(zhuǎn)化成整型就會直接損失了小數(shù)部位的數(shù)據(jù)，加上0.5可以達到四舍五入的效果。。。

坐在地平線

謝謝了，我明白了，呵呵