Perl 用if循环如何比较文字呢？

eddie_we

#! /usr/bin/perl -w
print "Enter the Butten where did you what to transfer C or F : \n";
chomp($e=<STDIN>);
$b="C";
if ($e=$b) {
print "Enter the C temp :  \n";
chomp($c=<STDIN>);
$f=(9/5)*$c+32;
print "The F temp is $f  F \n";
} else {
print "The F temp is: \n";
chomp($f=<STDIN>);
$c=($f-32)/(9/5);
print "The C temp is $c C. \n";
}

这样现在不对，哪怕输入F也是提示输入摄氏度，应该输入F就输入华氏的才对。

[root@eddie eddie]# ./temper
Enter the Butten where did you what to transfer C or F :
F
Enter the C temp :
34
The F temp is 93.2  F

eddie_we

搞好了，不容易。总算找到等于的表达方式了
#! /usr/bin/perl -w
print "Enter the Butten where did you what to transfer C or F : \n";
chomp($e=<STDIN>);
#$b="C";
if ($e=~C) {
print "Enter the C temp :  \n";
chomp($c=<STDIN>);
$f=(9/5)*$c+32;
print "The F temp is $f  F \n";
}
elsif ($e=~F) {
print "The F temp is: \n";
chomp($f=<STDIN>);
$c=($f-32)/(9/5);
print "The C temp is $c C. \n";
}
else {
print "You input a wrong string ! \n";
}

masterdemon

不对。

字符串==用  eq。
那个=~是正则表达式的match，即匹配。

字符串比较：
eq : equality
ne :  inequality
lt : less than
gt : greater than
le : less than or equal
ge  :greater than or equal

正则表达式
=~ :match
!~   : unmatch

eddie_we

可是用那个也能成啊。。。

dieken_qfz

1. 
   
2. print "===================================\n";
   
3. 
   
4. print "y or n ?\n";
   
5. $ch = getc(STDIN);
   
6. print "you selected :", $ch, "\n";
   
7. 
   
8. $ch = <STDIN>;   # skip the last input line
   
9. 
   
10. print "input a line: ";
    
11. $str = <STDIN>;
    
12. print "the first char is: ", chr(ord($str)), "\n";
    
13. if (ord('y') == ord($str)) {
    
14.         print "yes\n";
    
15. } else {
    
16.         print "no\n";
    
17. }
    
18. 
    
19. print "input: ";
    
20. $data = "";
    
21. read(STDIN, $data, 1);
    
22. print "read: \[$data\]\n";
    
23. if ('y' == $data) { print "yes\n"; }
    
24. else {print "no\n";}
    

复制代码

===================================
y or n ?
y
you selected :y
input a line: yes
the first char is: y
yes
input: y
read: [y]
yes


这段代码必须要每次输入回车才能继续,如果想
实现单击一个键不需要回车,可参考perlfunc中
的getc的说明。