Java-Switch功能
Down bellow是计算一个单词有多少元音的代码的一部分。第一个代码与第二个代码的功能相同，对吗？所以，如果我想使用几个具有相同操作的案例，我只需要将操作放在最后一个案例上（如第一个代码中） 第一:Java-Switch功能,java,switch-statement,Java,Switch Statement,Down bellow是计算一个单词有多少元音的代码的一部分。第一个代码与第二个代码的功能相同，对吗？所以，如果我想使用几个具有相同操作的案例，我只需要将操作放在最后一个案例上（如第一个代码中） 第一: public static int contvowel(String pal){ int cont=0; pal=pal.toLowerCase(); for(int i=0; i<pal.length();i++) {
public static int contvowel(String pal){
int cont=0;
pal=pal.toLowerCase();
for(int i=0; i<pal.length();i++) {
switch(pal.charAt(i)){
case 'a':
case 'e':
case 'i':
case 'o':
case 'u': { cont=cont+1; break; }
}
}
return cont;
}
公共静态int-cont元音（字符串pal）{
int cont=0；
pal=pal.toLowerCase（）；
对于（int i=0；i，您的答案是：
是的。第一个代码与第二个代码相同。回答您的问题，“是”-结果相同
但这里有一些值得思考的东西：
public static int countVowels(String pal) {
return pal.replaceAll("[^aeiou]", "").length();
}
是的结果和结果将是相同的。但辩护的否为“代码相同”
编辑：如评论中所述，这是两个编译版本：
第1版：
Compiled from "Hello.java"
public class main.java.Hello {
public main.java.Hello();
Code:
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: return
public static void main(java.lang.String[]);
Code:
0: ldc #2 // String Hello, World!
2: astore_1
3: iconst_0
4: istore_2
5: aload_1
6: invokevirtual #3 // Method java/lang/String.toLowerCase:()Ljava/lang/String;
9: astore_1
10: iconst_0
11: istore_3
12: iload_3
13: aload_1
14: invokevirtual #4 // Method java/lang/String.length:()I
17: if_icmpge 86
20: aload_1
21: iload_3
22: invokevirtual #5 // Method java/lang/String.charAt:(I)C
25: lookupswitch { // 5
97: 76
101: 76
105: 76
111: 76
117: 76
default: 80
}
76: iload_2
77: iconst_1
78: iadd
79: istore_2
80: iinc 3, 1
83: goto 12
86: getstatic #6 // Field java/lang/System.out:Ljava/io/PrintStream;
89: new #7 // class java/lang/StringBuilder
92: dup
93: invokespecial #8 // Method java/lang/StringBuilder."<init>":()V
96: ldc #9 // String Got:
98: invokevirtual #10 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
101: iload_2
102: invokevirtual #11 // Method java/lang/StringBuilder.append:(I)Ljava/lang/StringBuilder;
105: invokevirtual #12 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
108: invokevirtual #13 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
111: return
}
从“Hello.java”编译而来
公共类main.java.Hello{
public main.java.Hello（）；
代码：
0:aload_0
1:invokespecial#1//方法java/lang/Object。“：（）V
4：返回
公共静态void main（java.lang.String[]）；
代码：
0:ldc#2//String你好，世界！
2:astore_1
3:iconst_0
4:istore_2
5:aload_1
6:invokevirtual#3//方法java/lang/String.toLowerCase:（）Ljava/lang/String；
9:astore_1
10:iconst_0
11:istore_3
12:iload_3
13:aload_1
14:invokevirtual#4//方法java/lang/String.length:（）I
17:if_icmpge 86
20:aload_1
21:iload_3
22:invokevirtual#5//方法java/lang/String.charAt:（I）C
25：查找开关{//5
97: 76
101: 76
105: 76
111: 76
117: 76
默认值：80
}
76:iload_2
77:iconst_1
78:iadd
79:istore_2
80:iinc 3，1
83:转到12
86:getstatic#6//fieldjava/lang/System.out:Ljava/io/PrintStream；
89:new#7//class java/lang/StringBuilder
92:dup
93:invokespecial#8//方法java/lang/StringBuilder。”“：（）V
96:ldc#9//字符串已获取：
98:invokevirtual#10//方法java/lang/StringBuilder.append:（Ljava/lang/String；）Ljava/lang/StringBuilder；
101:iload_2
102:invokevirtual#11//方法java/lang/StringBuilder.append：（I）Ljava/lang/StringBuilder；
105:invokevirtual#12//方法java/lang/StringBuilder.toString:（）Ljava/lang/String；
108:invokevirtual#13//方法java/io/PrintStream.println:（Ljava/lang/String；）V
111：返回
}
第2版：
Compiled from "Hello.java"
public class main.java.Hello {
public main.java.Hello();
Code:
0: aload_0
1: invokespecial #1 // Method java/lang/Object."<init>":()V
4: return
public static void main(java.lang.String[]);
Code:
0: ldc #2 // String Hello, World!
2: astore_1
3: iconst_0
4: istore_2
5: aload_1
6: invokevirtual #3 // Method java/lang/String.toLowerCase:()Ljava/lang/String;
9: astore_1
10: iconst_0
11: istore_3
12: iload_3
13: aload_1
14: invokevirtual #4 // Method java/lang/String.length:()I
17: if_icmpge 114
20: aload_1
21: iload_3
22: invokevirtual #5 // Method java/lang/String.charAt:(I)C
25: lookupswitch { // 5
97: 76
101: 83
105: 90
111: 97
117: 104
default: 108
}
76: iload_2
77: iconst_1
78: iadd
79: istore_2
80: goto 108
83: iload_2
84: iconst_1
85: iadd
86: istore_2
87: goto 108
90: iload_2
91: iconst_1
92: iadd
93: istore_2
94: goto 108
97: iload_2
98: iconst_1
99: iadd
100: istore_2
101: goto 108
104: iload_2
105: iconst_1
106: iadd
107: istore_2
108: iinc 3, 1
111: goto 12
114: getstatic #6 // Field java/lang/System.out:Ljava/io/PrintStream;
117: new #7 // class java/lang/StringBuilder
120: dup
121: invokespecial #8 // Method java/lang/StringBuilder."<init>":()V
124: ldc #9 // String Got:
126: invokevirtual #10 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
129: iload_2
130: invokevirtual #11 // Method java/lang/StringBuilder.append:(I)Ljava/lang/StringBuilder;
133: invokevirtual #12 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
136: invokevirtual #13 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
139: return
}
从“Hello.java”编译而来
公共类main.java.Hello{
public main.java.Hello（）；
代码：
0:aload_0
1:invokespecial#1//方法java/lang/Object。“：（）V
4：返回
公共静态void main（java.lang.String[]）；
代码：
0:ldc#2//String你好，世界！
2:astore_1
3:iconst_0
4:istore_2
5:aload_1
6:invokevirtual#3//方法java/lang/String.toLowerCase:（）Ljava/lang/String；
9:astore_1
10:iconst_0
11:istore_3
12:iload_3
13:aload_1
14:invokevirtual#4//方法java/lang/String.length:（）I
17:if_icmpge 114
20:aload_1
21:iload_3
22:invokevirtual#5//方法java/lang/String.charAt:（I）C
25：查找开关{//5
97: 76
101: 83
105: 90
111: 97
117: 104
默认值：108
}
76:iload_2
77:iconst_1
78:iadd
79:istore_2
80:转到108
83:iload_2
84:iconst_1
85:iadd
86:istore_2
87:转到108
90:iload_2
91:iconst_1
92:iadd
93:istore_2
94:转到108
97:iload_2
98:iconst_1
99:iadd
100:istore_2
101:转到108
104:iload_2
105:iconst_1
106:iadd
107:istore_2
108:iinc 3，1
111:转到12
114:getstatic#6//Field java/lang/System.out:Ljava/io/PrintStream；
117:new#7//class java/lang/StringBuilder
120:dup
121:invokespecial#8//方法java/lang/StringBuilder。”“：（）V
124:ldc#9//字符串已获取：
126:invokevirtual#10//方法java/lang/StringBuilder.append:（Ljava/lang/String；）Ljava/lang/StringBuilder；
129:iload_2
130:invokevirtual#11//方法java/lang/StringBuilder.append：（I）Ljava/lang/StringBuilder；
133:invokevirtual#12//方法java/lang/StringBuilder.toString:（）Ljava/lang/String；
136:invokevirtual#13//方法java/io/PrintStream.println:（Ljava/lang/String；）V
139：返回
}
diff-e ou1 ou2
39,51c
80: goto 108
83: iload_2
84: iconst_1
85: iadd
86: istore_2
87: goto 108
90: iload_2
91: iconst_1
92: iadd
93: istore_2
94: goto 108
97: iload_2
98: iconst_1
99: iadd
100: istore_2
101: goto 108
104: iload_2
105: iconst_1
106: iadd
107: istore_2
108: iinc 3, 1
111: goto 12
114: getstatic #6 // Field java/lang/System.out:Ljava/io/PrintStream;
117: new #7 // class java/lang/StringBuilder
120: dup
121: invokespecial #8 // Method java/lang/StringBuilder."<init>":()V
124: ldc #9 // String Got:
126: invokevirtual #10 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
129: iload_2
130: invokevirtual #11 // Method java/lang/StringBuilder.append:(I)Ljava/lang/StringBuilder;
133: invokevirtual #12 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
136: invokevirtual #13 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
139: return
.
29,33c
101: 83
105: 90
111: 97
117: 104
default: 108
.
23c
17: if_icmpge 114
39,51c
80:转到108
83:iload_2
84:iconst_1
85:iadd
86:istore_2
87:转到108
90:iload_2
91:iconst_1
92:iadd
93:istore_2
39,51c
80: goto 108
83: iload_2
84: iconst_1
85: iadd
86: istore_2
87: goto 108
90: iload_2
91: iconst_1
92: iadd
93: istore_2
94: goto 108
97: iload_2
98: iconst_1
99: iadd
100: istore_2
101: goto 108
104: iload_2
105: iconst_1
106: iadd
107: istore_2
108: iinc 3, 1
111: goto 12
114: getstatic #6 // Field java/lang/System.out:Ljava/io/PrintStream;
117: new #7 // class java/lang/StringBuilder
120: dup
121: invokespecial #8 // Method java/lang/StringBuilder."<init>":()V
124: ldc #9 // String Got:
126: invokevirtual #10 // Method java/lang/StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
129: iload_2
130: invokevirtual #11 // Method java/lang/StringBuilder.append:(I)Ljava/lang/StringBuilder;
133: invokevirtual #12 // Method java/lang/StringBuilder.toString:()Ljava/lang/String;
136: invokevirtual #13 // Method java/io/PrintStream.println:(Ljava/lang/String;)V
139: return
.
29,33c
101: 83
105: 90
111: 97
117: 104
default: 108
.
23c
17: if_icmpge 114