所以我们有一个令牌器的代码，这个代码确实有点破碎。
现在我们无法修改此功能。
尽管如此，它为大多数情况提供了正确的输出。除了在某些情况下，它会添加随机的额外垃圾。
现在，程序读入一个字符串并将其转换为树以供执行。最底层的节点包含简单的命令。
必须解析这些简单的命令才能执行。
现在在解析过程中发现最后的额外垃圾阻碍了execvp（）调用。
我想询问有关如何在最后消除垃圾的建议。
我想过使用正则表达式来检查字符串是否包含有效字符，并且好奇是否有任何标准库函数可以帮助解决这个问题？
如果它有任何区别 - 垃圾字符就像一个带
的方框00
19
作为其内容。它显示在gedit中但不在此处。垃圾打印的起源是第一个解析，更改它是不可行的。
以下是该程序的示例运行。
sgml@SGML3:~/smelly-fish$ ./timetrash exectest
Word is: expr 3 + 8 + 9 + 8 (Junk - this character won't display)
Temp is: expr 3 + 8 + 9 + 8 (Junk - this character won't display)
c->u.word[0] is expr
c->u.word[1] is 3
c->u.word[2] is +
c->u.word[3] is 8
c->u.word[4] is +
c->u.word[5] is 9
c->u.word[6] is +
c->u.word[7] is 8
c->u.word[8] is (Junk - this character won't display)
c->u.word[9] is (null)
expr: syntax error
Command is: SIMPLE_COMMAND
Word is: expr 7 + 8 + 9 + 8 (Junk - this character won't display)
Temp is: expr 7 + 8 + 9 + 8 (Junk - this character won't display)
c->u.word[0] is expr
c->u.word[1] is 7
c->u.word[2] is +
c->u.word[3] is 8
c->u.word[4] is +
c->u.word[5] is 9
c->u.word[6] is +
c->u.word[7] is 8
c->u.word[8] is (Junk - this character won't display)
c->u.word[9] is (null)
expr: syntax error
Command is: SIMPLE_COMMAND
sgml@SGML3:~/smelly-fish$ ./timetrash exectest >execresults1.txt
expr: syntax error
expr: syntax error
sgml@SGML3:~/smelly-fish$ ./timetrash exectest
Word is: expr 3 + 8 + 9 + 8 (Junk - this character won't display)
Temp is: expr 3 + 8 + 9 + 8 (Junk - this character won't display)
c->u.word[0] is expr
c->u.word[1] is 3
c->u.word[2] is +
c->u.word[3] is 8
c->u.word[4] is +
c->u.word[5] is 9
c->u.word[6] is +
c->u.word[7] is 8
c->u.word[8] is (Junk - this character won't display)
c->u.word[9] is (null)
expr: syntax error
Command is: SIMPLE_COMMAND
Word is: expr 7 + 8 + 9 + 8
Temp is: expr 7 + 8 + 9 + 8
c->u.word[0] is expr
c->u.word[1] is 7
c->u.word[2] is +
c->u.word[3] is 8
c->u.word[4] is +
c->u.word[5] is 9
c->u.word[6] is +
c->u.word[7] is 8
c->u.word[8] is
c->u.word[9] is (null)
expr: syntax error
Command is: SIMPLE_COMMAND
sgml@SGML3:~/smelly-fish$