can someone explain me what does _i64toa_s function does in c++ ?
and what is the equivalent in Java?
I didn't find any documentation on this function.
It converts a 64-bit integer into a string. The java equivalent is Long.toString(value).
Oh, and there is some documentation here: https://msdn.microsoft.com/en-us/library/0we9x30h.aspx
Related
C method _strtod_l can convert string "13.361389" to double value 13.361389000000001 , is there equivalent in C# and Java also can get the same result? I found the Convert.ToDouble in C# cannot do it.
For C# you can use Double.Parse("13.361389", CultureInfo.InvariantCulture)
For Java you can use Double.parseDouble("13.361389")
I am trying to translate some C# code into java and would like to know what is the java equivalent of System.Convert.ToInt32(char):
Converts the value of the specified Unicode character to the
equivalent 32-bit signed integer.
Convert.ToInt32(letter);
"Convert.ToInt32(someChar)" does exactly what "(int)someChar" does.
Since "(int)someChar" is available in Java, why not use that?
When testing the various options, use '5' as a test - some options will convert this simply to the integer 5, but you will want the integer 53 to match the original C# behavior of Convert.ToInt32.
I have the below Java code:
String Str1 = new String("Welcome to Tutorialspoint.com");
System.out.println(Str1.toString().getBytes("UTF-8"));
The output on a 64-bit Windows 7 machine is: "[B#7041825e".
What would be the above code's PHP equivalent?
There isn't. PHP doesn't have a distinction between strings and a bunch of bytes.
You may use strlen() for that purpose.
In your case, mb_strlen() will do.
... for more reading: http://php.net/manual/en/function.mb-strlen.php
This question already has answers here:
Method for evaluating math expressions in Java
(8 answers)
Closed 9 years ago.
I tried searching for it via google and here but I'm not finding questions to what I mean (search engines don't understand the context by which I mean function).
Essentially I want to do the following
double f(String function, double a){
return function.Function(a);
}
What would happen is the string function is of the form "x^2+2" it would likely be converted somehow to "x.pow(2) + 2" and then x is replaced by a and the result of the function is returned.
Is there any Java class or method that does what I said (or simple way to do it)? Or any code from another source that does what I said or a variant.
I don't have to code what I said, I just need f(x) to solve root finding problems for any function string passed as input. I thought Java would have such a method somewhere but I can't find it.
So, in Java you have an essential problem because you cannot directly convert a String to a mathematical expression. Your options are as follows:
Search for a library that can convert a particularly formatted string to a mathematical expression.
Parse the string yourself. String parsing is difficult and error prone, and the Java around this would be difficult.
Use Scala, which would allow you to directly compose functions to pass into your function, rather than trying to do the expensive conversion from a human-readable string to a machine-interpretable function. Note that Scala is interoperable with Java, but has a bit of a learning curve. Other functional languages can handle this as well, but may lack interoperability.
I'm trying to port a Matlab code to Java and C++.
It's quite straightforward however I find a function that is more than simple operations, it numerically evaluates integral:
lungh=quad('normpp',0,1,[],[],x1,x2,x3,x4,x5,x6,x7,y1,y2,y3,y4,y5,y6,y7);
Here x1,...,x8 and y1,...,y7 are simple numbers.
First of all, how do this parameters are interpreted? How does this function work?
I think that 0 and 1 are the bounds of the integral...but what about the others?? Especially 'normpp' and []?
I read the quad help but I didn't understand how it works with such an amount of parameters.
The second problem is: Do exist a java and a C++ libraries that offer these function?
I would prefer to do it directly in Java and C++ without calling Matlab.
Thanks!
In C there is a very nice library : The Gnu Scientific Library (GSL).
Here is a link to the Numerical integration page of the GSL :
GSL
The use of this library in a C++ project is straight forward.
I think the function gsl_integration_qag is a good choice to replace the matlab quad function.