/ Floating-point number tests float u, v, w; / applies to doubles, too Float ()i tFloat( printFloat(v,v) printFloat("w" u=v+ wi printEloat("v+ w", u) u=v-w; printFloat ("v-w",u) u=v* wi printFloat("v *w",u)i wi p / the following works for / char, by and double: u + vi printFloat ("u + v", u) i printFloat (u -=v", u) tFloat ("u * u/= v; printFloat("u/= v", u) monitor. expect (new string[] t 号号方 ?\\d+m 各k=-?\d+ 号号j\1+k d+", 告号j-k=-2\\d+ 号k/j=-?1\d+", 各号k\\ 号kj ?\\d+ 各号方=k ?\\d+m 号各 ?\\d+\.\d+(E-?\\d)?", 各号W=-?\d+\\.\d+(E-?\d)? 各号V+W=-?\d+.\d+(E-?\d)?? =-2\\d+\\.\\d+(E-?\\d)??", 号号V ?\\d+\\.\\d+(E-?\\d)??", ?\\d+\\.\\d+(E-?\\d)?? 号号u\\+=V=-?\d+\\.\d+(E-?\\d)?? V=-?\d+\.d+(E-?\\d)??", 号号u*=V=-?\d+\.\\d+(E-2\d)??”, 各号u/=V=-?\d+).\d+(E-?\hd)?? }); ///:~ 首先看到的是两个为节省敲键盘而定义的打印方法: printing()会先打 印一个 String,然后再接一个int:而 printFloat()会先打印一个 String,再打印一个 float 程序先创建一个 Random对象,以产生数字。由于创建过程中没有使用 参数,因此Java会用当前的时间作随机数生成器的种子。程序用 Random对象的 nextInt()和 nextFloat()方法生成了很多不同种 类的随机数(你也可以用 nextLong()或 nextDouble() 取模运算符( modulus operator)会将随机数生成器产生的数字限制在操 作数减一的范围之内(这里就是99) 正则表达式( Regular expressions) 第7页共48页shhgs@wgqqh.com ￾ 7 ✁ ✂ 48 ✁ // Floating-point number tests: float u,v,w; // applies to doubles, too v = rand.nextFloat(); w = rand.nextFloat(); printFloat("v", v); printFloat("w", w); u = v + w; printFloat("v + w", u); u = v - w; printFloat("v - w", u); u = v * w; printFloat("v * w", u); u = v / w; printFloat("v / w", u); // the following also works for // char, byte, short, int, long, // and double: u += v; printFloat("u += v", u); u -= v; printFloat("u -= v", u); u *= v; printFloat("u *= v", u); u /= v; printFloat("u /= v", u); monitor.expect(new String[] { "%% j = -?\\d+", "%% k = -?\\d+", "%% j \\+ k = -?\\d+", "%% j - k = -?\\d+", "%% k / j = -?\\d+", "%% k \\* j = -?\\d+", "%% k % j = -?\\d+", "%% j %= k = -?\\d+", "%% v = -?\\d+\\.\\d+(E-?\\d)?", "%% w = -?\\d+\\.\\d+(E-?\\d)?", "%% v \\+ w = -?\\d+\\.\\d+(E-?\\d)??", "%% v - w = -?\\d+\\.\\d+(E-?\\d)??", "%% v \\* w = -?\\d+\\.\\d+(E-?\\d)??", "%% v / w = -?\\d+\\.\\d+(E-?\\d)??", "%% u \\+= v = -?\\d+\\.\\d+(E-?\\d)??", "%% u -= v = -?\\d+\\.\\d+(E-?\\d)??", "%% u \\*= v = -?\\d+\\.\\d+(E-?\\d)??", "%% u /= v = -?\\d+\\.\\d+(E-?\\d)??" }); } } ///:~ ~/<g(eיåæçèéàOä(]ªµ0prin tIn t( )º/] ª3× Strin g|Á3× in t à prin tFl oat( )º/]ª3× Strin gÁ]ª3× fl oat â/§¨3× Ran dom ¥_EJ0"†`)§¨^â*œmçˆ "æò Java ºˆ (41¸ê"0Ž¾(†âˆ Ran dom ¥_( nextIn t( ) nextFl oat( )µ0Ž,ŠVX‡† e(¸ê" (¡[ÝEˆ nextLon g( )… nextDou ble( )) ÜÝ (m odul us operator)º¸ê"0Ž¾J0("†ë!F 1"P3(ìíu ( Ë 99)  ( Regu lar expression s)