#Java math equation converter

1 messages · Page 1 of 1 (latest)

dull elbow
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I want to use an engine to convert a string of a simple math equation to an actual equation. The code compiles but the engine isn't found. Code: ```java
// Create a new Script engine
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = manager.getEngineByName("JavaScript");

    // Calculation
    try {
        Object result = engine.eval(equation);
        System.out.println("Result: " + result);
    } catch (ScriptException e) {
        System.out.println("ERROR: Something went wrong with the equation");
    }
late hedgeBOT
#

<@&987246399047479336> please have a look, thanks.

late hedgeBOT
#

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#

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#

a ScriptEngineManager
ScriptEngineManager manager = new ScriptEngineManager();

    // Get the JavaScript engine
    ScriptEngine engine = manager.getEngineByName("JavaScript");
    
    // Define the math equation as a string
    String equation = "2 + 3 * 4";
    
    try {
        // Evaluate the math equation using the JavaScript engine
        Object result = engine.eval(equation);
        
        // Print the result
        System.out.println(result);
    } catch (ScriptException e) {
        e.printStackTrace();
    }
}

}


Explanation:

1. Create a `ScriptEngineManager` object to manage script engines.
2. Use the `getEngineByName()` method of the `ScriptEngineManager` to get a specific script engine. In this case, we want to use the JavaScript engine, so we pass "JavaScript" as the argument.
3. Define your math equation as a string. In this example, we have "2 + 3 * 4".
4. Use the `eval()` method of the script engine to evaluate the math equation and store the result in an `Object` variable.
5. Print the result.

Make sure you have imported necessary classes like `javax.script.ScriptEngineManager` and `javax.script.ScriptException`.
pastel cargo
dull elbow
exotic coral
#

there exists libraries that can evaluate math expressions

pastel cargo
pastel cargo
dull elbow
twin mountainBOT
#
JShell
📦 jdk.jshell/jdk.jshell 
public class JShell implements AutoCloseable

The JShell evaluation state engine. This is the central class in the JShell API. A JShell instance holds the evolving compilation and execution state. The state is changed with the instance methods eval(String), drop(Snippet) and addToClasspath(String). The majority of methods query the state. A JShell instance also allows registering for events with onSnippetEvent(Consumer) and onShutdown(Consumer), which are unregistered with unsubscribe(Subscription). Access to the source analysis utilities is via #sourceCodeAnalysis. When complete the instance should be closed to free resources -- #close().

An instance of JShell is created with JShell.create().

This class is not thread safe, except as noted, all access should be through a single thread.

author

Robert Field

since

9

✨ Click the white name at the top to open the online javadoc.
pastel cargo
#

well

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problem is security

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if you want to allow some unknown user to do math

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here it's not just math that they can do

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and this is a problem

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same if you use js

pastel cargo