I am currently programming in ST (TwinCat), but two errors occured, which I do not understand at all.
Error-Code says:
(1) (TRUE AND TON_01.Q) is no valid assignment target
(2) Q is no input of TOF
I already declared Q as my Output , but TON and TOF cannot handle it. The Code and the Error is attached to the post. enter image description here
Thank you for your Help.
The problem is that you are doing an assignment of TOF_01.Q and not a check.
So instead of:
IF TOF_01.Q := TRUE ... it should be
IF TOF_01.Q = TRUE ... or simply
IF TOF_01.Q...
Same with TON_01.Q obviously.
Related
I read other questions about the "slice bounds of range" here in the stackoverflow, but none of them using the same context from this.
Then, none of the answers helped me.
In my use case, the "golang's syntax" of substring using [] doesn't return an error variable. It launches a runtime error using the "panic" instruction.
My goal is to avoid to reach on the "panic" instruction.
I need to treat this error and provide messages that describe with more details the context around the moment where this error had occurred.
Obs:
The content of the string variable which one I need to get the substring value is totally dynamic and the indexes that I have been using to get the substring value is equally calculated dynamically.
You need to do bounds checking on your indexes:
if j >= 0 && j <= len(str) {
y = str[:j]
}
I have been trying to teach myself to code and have gravitated towards Ruby.
Upon working on if functions I have come across this problem where even if the user input is == to the answer variable it still comes back as false in the if function. It will not come back as true
I can get it to work if it is an Integer, but for some reason it always returns false when having a string. Tried to convert is as well but can not figure it out.
Thank you for any help.
puts("For each question select A, B, or C")
puts("What is the capital of Kentucky?")
puts()
puts("A. Louisville")
puts("B. Frankfort")
puts("C. Bardstown")
puts()
answer = String("B")
text = gets()
puts()
if text == answer
puts("correct")
else
puts("incorrect")
puts("The correct answer was " + answer + ".")
end
There is an additional method you can call when declaring the "text" variable that will solve this.
The method you used preserves a line break at the end when you press enter to submit an answer so it will never actually correspond to the answer. To remove the line break use the "chomp" method.
text = gets.chomp
Hope this helped. Good luck.
This question is mostly out of interest to understand the functionality of VBScript better. I recognize that I can simply do some casting to know what to expect from my code, but in my situation I want to understand why casting, or any "workaround", is needed. For simplicity, here's the basic idea of my code:
variable1 = 1
Public Function findSomethingInATextString(par1, par2)
[...searching with a Do Until loop code here...]
Result = 1
If([par2 is found in par1]) Then
Result = 0
End If
Return Result
End Function
variable1 = findSomethingInATextString("Hello World", "Hello")
When I run this I get a Type Mismatch error. I don't understand why that's the case. variable1 is an integer and findSomethingInAString() returns an integer. They appear to be the same data type.
I'm working in a restricted environment where I can't do much debugging (it's painfully slow to code in this program...). So at the moment I'm unable to say what data type this is coming out as - I just know that it's apparently not integer.
After all that, and to make sure my question is clear, I'm intrigued to know what the return type of my function is (if someone happens to know), but my real question is: Why isn't the return type matching with variable1?
Use the minimal script
Return
Output
cscript 36633603.vbs
...36633603.vbs(1, 1) Microsoft VBScript runtime error: Type mismatch: 'return'
to prove to yourself, that just mentioning return in a VBScript will throw a type mismatch error.
Believe JosefZ's comment that VBScript returns function values by assigning to the function's name. Better: Read the docs (before you try to write code).
Evidence:
Function f1()
f1 = 1
End Function
WScript.Echo f1(), TypeName(f1())
Output:
cscript 36633603.vbs
1 Integer
I will do an exam tomorrow, but now I can't run it, can anyone help me?? Thanks!!
program v2
uses
crt;
var
t, dongia: real;
begin
clrscr;
write('nhap t='); readln(t);
if dongia >= 100000 then
t:= 70 / 100 * dongia;
writeln('in don gia:'t);
readln;
end.
Add a semi colon (;) after the program name (so v2;)
Add a comma between the string literal and "t", so ( 'in don gia:',t )
as Roy says in the comments, the logic of your program is wrong. Dongia is uninitialized before the check.
Next time, add a problem description including errormessages and show that you spent some effort/thought in finding the problem.
Put parentheses around the IF condition:
if (dongia>=100000) then
and you should also put a comma in the writeln:
writeln('in don gia:', t);
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Does VB6 short-circuit complex conditions?
I am curious about how IF statements are executed in VB6.
For example if I have the statement
If x And y Then
'execute some code
End If
Does the code move on if x is not true? Or does it go ahead and evaluate y even though there is no logical point?
Another example
If x Or y Then
'execute some code
End If
Does the code continue and evaluate y if x is true?
EDIT:
Is there a way to avoid nested IF statements if I want to evaluate very complex conditions and I don't want to waste CPU time?
What you are describing is short circuiting logic, and VB6 doesn't have it...
For example, in VB.Net you might write
If x AndAlso y then...
In this case y is not tested if x turns out to be false.
In your VB6 example, you'll get a Object or With block variable not set error if you try something such as:
Dim x as Object
If Not x Is Nothing And x.y=1 Then
Since object x has not been instantiated.
An unwieldy or-like statement that exhibits short circuiting behaviour:
select case True
case a(), b(), c()
'//if a returns true b & c are not invoked, if b returns true a & b were invoked
case else
...
To answer your edit - avoiding nested IF statements, you can use Select Case, covered in the latter half of this article.
Code snippet from the article:
Select Case strShiftCode
Case "1"
sngShiftRate = sngHourlyRate
Case "2"
sngShiftRate = sngHourlyRate * 1.1
Case "3"
sngShiftRate = sngHourlyRate * 1.5
Case Else
Print "Shift Code Error"
End Select