语法:round(x,prec)

参数 描述

x 可选,规定要舍入的数字.

prec 可选,规定小数点后的位数.

说明:返回将 x 根据指定精度 prec(十进制小数点后数字的数目)进行四舍五入的结果,prec 也可以是负数或零(默认值).

提示和注释

注释:php默认不能正确处理类似 "12,300.2" 的字符串.

注释:prec 参数是在 php 4 中被引入的,实例代码如下:

1. <?php
2. */
3. echo round(3.4); //输出3
4. echo "<br>";
5. echo round(3.5); //输出4
6. echo "<br>";
7. echo round(3.6); //输出4
8. echo "<br>";
9. echo round(3.6,0); //输出4
10. echo "<br>";
11. echo round(1.95583,2); //输出1.96
12. echo "<br>";
13. echo round(1241757,-3); //输出1242000
14. echo "<br>";
15. echo round(4.045,2); //输出4.05
16. //开源代码phpfensi.com
17. echo "<br>";
18. echo round(4.055,2); //输出4.06
19. //使用stdround函数代替php的round函数
20. ?>
21. <?php
22. function stdround($num, $d=0)
23. {
24. return round($num + 0.0001 / pow(10, $d), $d);
25. }
26. echo "round(1.005,2)= ".round(1.005,2). "n ";
27. echo "round(1.015,2)= ".round(1.015,2). "n ";
28. echo "round(1.025,2)= ".round(1.025,2). "n ";
29. echo "round(1.035,2)= ".round(1.035,2). "n ";
30. echo "round(1.045,2)= ".round(1.045,2). "n ";
31. echo "round(1.055,2)= ".round(1.055,2). "n ";
32. echo "round(1.065,2)= ".round(1.065,2). "n ";
33. echo "round(1.075,2)= ".round(1.075,2). "n ";
34. echo "round(1.085,2)= ".round(1.085,2). "n ";
35. echo "round(1.095,2)= ".round(1.095,2). "n ";
36. echo "stdround(1.005,2)= ".stdround(1.005,2). "n ";
37. echo "stdround(1.015,2)= ".stdround(1.015,2). "n ";
38. echo "stdround(1.025,2)= ".stdround(1.025,2). "n ";
39. echo "stdround(1.035,2)= ".stdround(1.035,2). "n ";
40. echo "stdround(1.045,2)= ".stdround(1.045,2). "n ";
41. echo "stdround(1.055,2)= ".stdround(1.055,2). "n ";
42. echo "stdround(1.065,2)= ".stdround(1.065,2). "n ";
43. echo "stdround(1.075,2)= ".stdround(1.075,2). "n ";
44. echo "stdround(1.085,2)= ".stdround(1.085,2). "n ";
45. echo "stdround(1.095,2)= ".stdround(1.095,2). "n ";
46. $m=0.000000000000001;
47. echo "n ";
48. echo "round(1.005+{$m},2)= ".round(1.005+$m,2). "n ";
49. echo "round(1.015+{$m},2)= ".round(1.015+$m,2). "n ";
50. echo "round(1.025+{$m},2)= ".round(1.025+$m,2). "n ";
51. echo "round(1.035+{$m},2)= ".round(1.035+$m,2). "n ";
52. echo "round(1.045+{$m},2)= ".round(1.045+$m,2). "n ";
53. echo "round(1.055+{$m},2)= ".round(1.055+$m,2). "n ";
54. echo "round(1.065+{$m},2)= ".round(1.065+$m,2). "n ";
55. echo "round(1.075+{$m},2)= ".round(1.075+$m,2). "n ";
56. echo "round(1.085+{$m},2)= ".round(1.085+$m,2). "n ";
57. echo "round(1.095+{$m},2)= ".round(1.095+$m,2). "n ";
58. echo "round(1.005,2)= ".round(1.005,2). "n ";
59. echo "round(1.015,2)= ".round(1.015,2). "n ";
60. echo "round(1.025,2)= ".round(1.025,2). "n ";
61. echo "round(1.035,2)= ".round(1.035,2). "n ";
62. echo "round(1.045,2)= ".round(1.045,2). "n ";
63. echo "round(1.055,2)= ".round(1.055,2). "n ";
64. echo "round(1.065,2)= ".round(1.065,2). "n ";
65. echo "round(1.075,2)= ".round(1.075,2). "n ";
66. echo "round(1.085,2)= ".round(1.085,2). "n ";
67. echo "round(1.095,2)= ".round(1.095,2). "n ";
68. ?>