编程题:《语言解释器》
作者:互联网
一、语言解释器
描述:
实现一个简单的语言解释器,支持以下指令:
指令格式 | 描述 |
---|---|
mov a v | 把数v赋值给a,其中a是变量名称,由不超过10个小写字母组成,v是变量名或者常数(常数为-10000~10000的整数) |
inc a | 变量a加1 |
dec a | 变量a减1 |
jnz a v | 如果变量a的值不是0,则相对跳转v条指令。比如-2,向上跳转两个指令 |
输入保证最多有100个变量,100条语句;执行inc, dec和jnz之前,相应变量一定已经用mov赋值过。
输入:
- mov bx 2
- mov ax 5
- inc bx
- dec ax
- jnz ax -2
- dec ax
输出:
- ax -1
- bx 7
–尽量优化性能
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
public class Instructions {
private static int counter=0;
public static int getCounter() {
return Instructions.counter;
}
public static void setCounter(int counter) {
Instructions.counter=counter;
}
public static void setCounterPlus() {
Instructions.counter--;
}
public static void main(String[] args) {
List<String> instructions = new ArrayList<>();
Scanner scanner = new Scanner(System.in);
boolean flag =true;
System.out.println("请输入您的指令集----注:输入false会停止输入,且最多能输入100条");
int count =0;
while (flag) {
count++;
String nextLine = scanner.nextLine();
if ("false".equals(nextLine) || count >= 100) {
flag = false;
}
//System.out.println(nextLine.matches("\\s*mov\\s[a-z]{1,10}\\s((-?[1-9][0-9]{0,3})|([1-9][0-9]{0,3}))\\s*"));
if ( nextLine.matches("\\s*mov\\s[a-z]{1,10}\\s((-?[1-9][0-9]{0,4})|([1-9][0-9]{0,4}))\\s*")
|| nextLine.matches("\\s*jnz\\s[a-z]{1,10}\\s((-?[1-9][0-9]{0,4})|([1-9][0-9]{0,4}))\\s*")
|| nextLine.matches("\\s*inc\\s[a-z]{1,10}\\s*")
|| nextLine.matches("\\s*dec\\s[a-z]{1,10}\\s*")
){
instructions.add(nextLine);
System.out.println(nextLine);
}else if("false".equals(nextLine)){
System.out.println("输入完成");
}else {
System.out.println("您输入的指令:"+nextLine+"\t格式错误请重新输出");
}
}
//开始计算
ConcurrentHashMap<String,Integer> calculation = calculation(instructions);
System.out.println(calculation.toString());
}
public static ConcurrentHashMap calculation(List<String> instructions){
ConcurrentHashMap<String,Integer> mov = new ConcurrentHashMap<>();
boolean flag =true;
setCounter(instructions.size());
while (flag){
String instruction = instructions.get(Math.abs(instructions.size()-getCounter()));
if ((instruction.indexOf("mov"))>-1){
String[] split = instruction.trim().split(" ");
mov.put(split[1],Integer.valueOf(split[2]));
setCounterPlus();
}else if ((instruction.indexOf("inc"))>-1){
String[] split = instruction.trim().split(" ");
Integer integer = mov.get(split[1]);
mov.put(split[1],integer+1);
setCounterPlus();
} else if ((instruction.indexOf("dec"))>-1) {
String[] split = instruction.trim().split(" ");
Integer integer = mov.get(split[1]);
mov.put(split[1],integer-1);
setCounterPlus();
}else if((instruction.indexOf("jnz"))>-1){
String[] split = instruction.trim().split(" ");
Integer integer = mov.get(split[1]);
if (integer!=0){
int counter = getCounter();
setCounter(counter - Integer.valueOf(split[2]).intValue());
}else {
setCounterPlus();
}
}
if (getCounter()<=0){
flag=false;
}
}
return mov;
}
}
哪里写的不好,请大佬指点
标签:nextLine,解释器,instruction,语言,编程,mov,split,instructions,counter 来源: https://blog.csdn.net/wangxiangwen1998/article/details/122384767