# “if” and “iff” functions

## Case 1: Mechanics of the if function

// JAVA: import org.mariuszgromada.math.mxparser.*;
// ...
Expression e1 = new Expression("if(2<3, 1, 2)");
Expression e2 = new Expression("if(4<3, 1, 2)");
mXparser.consolePrintln("Res 1: " + e1.getExpressionString() + " = " + e1.calculate());
mXparser.consolePrintln("Res 2: " + e2.getExpressionString() + " = " + e2.calculate());

[mXparser-v.5.2.1] Res 1: if(2<3, 1, 2) = 1.0
[mXparser-v.5.2.1] Res 2: if(4<3, 1, 2) = 2.0


## Case 2: “if” function and arguments

// JAVA: import org.mariuszgromada.math.mxparser.*;
// ...
Argument x = new Argument("x = 2");
Expression e = new Expression("if(x<3, x+2, x-2)", x);
mXparser.consolePrintln("Res 1: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());
x.setArgumentValue(4);
mXparser.consolePrintln("Res 2: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());

[mXparser-v.5.2.1] Res 1:  x = 2.0, if(x<3, x+2, x-2) = 4.0
[mXparser-v.5.2.1] Res 2:  x = 4.0, if(x<3, x+2, x-2) = 2.0


## Case 3: “if” function in user defined function

// JAVA: import org.mariuszgromada.math.mxparser.*;
// ...
Function f = new Function("f(x) = if(x<3, x+2, x-2)");
Expression e1 = new Expression("f(2)", f);
Expression e2 = new Expression("f(4)", f);
mXparser.consolePrintln("Res 1: " + e1.getExpressionString() + " = " + e1.calculate());
mXparser.consolePrintln("Res 2: " + e2.getExpressionString() + " = " + e2.calculate());

[mXparser-v.5.2.1] Res 1: f(2) = 4.0
[mXparser-v.5.2.1] Res 2: f(4) = 2.0


## Case 4: Mechanics of the “iff” function

// JAVA: import org.mariuszgromada.math.mxparser.*;
// ...
Argument x = new Argument("x = 0.5");
Expression e = new Expression("iff(x<1, 1; x<2, 2; x<3, 3)", x);
mXparser.consolePrintln("Res 1: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());
x.setArgumentValue(1.5);
mXparser.consolePrintln("Res 2: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());
x.setArgumentValue(2.5);
mXparser.consolePrintln("Res 3: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());
x.setArgumentValue(3.5);
mXparser.consolePrintln("Res 4: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());

[mXparser-v.5.2.1] Res 1:  x = 0.5, iff(x<1, 1; x<2, 2; x<3, 3) = 1.0
[mXparser-v.5.2.1] Res 2:  x = 1.5, iff(x<1, 1; x<2, 2; x<3, 3) = 2.0
[mXparser-v.5.2.1] Res 3:  x = 2.5, iff(x<1, 1; x<2, 2; x<3, 3) = 3.0
[mXparser-v.5.2.1] Res 4:  x = 3.5, iff(x<1, 1; x<2, 2; x<3, 3) = NaN


## Case 5: “iff” function is not limited in number of cases

// JAVA: import org.mariuszgromada.math.mxparser.*;
// ...
Argument x = new Argument("x = 0.5");
Expression e = new Expression("iff(x<1, 1; x<2, 2; x<3, 3; x<4, 4; x<5, 5)", x);
mXparser.consolePrintln("Res 1: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());
x.setArgumentValue(1.5);
mXparser.consolePrintln("Res 2: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());
x.setArgumentValue(2.5);
mXparser.consolePrintln("Res 3: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());
x.setArgumentValue(3.5);
mXparser.consolePrintln("Res 4: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());
x.setArgumentValue(4.5);
mXparser.consolePrintln("Res 5: " + " x = " + x.getArgumentValue() + ", " + e.getExpressionString() + " = " + e.calculate());

[mXparser-v.5.2.1] Res 1:  x = 0.5, iff(x<1, 1; x<2, 2; x<3, 3; x<4, 4; x<5, 5) = 1.0
[mXparser-v.5.2.1] Res 2:  x = 1.5, iff(x<1, 1; x<2, 2; x<3, 3; x<4, 4; x<5, 5) = 2.0
[mXparser-v.5.2.1] Res 3:  x = 2.5, iff(x<1, 1; x<2, 2; x<3, 3; x<4, 4; x<5, 5) = 3.0
[mXparser-v.5.2.1] Res 4:  x = 3.5, iff(x<1, 1; x<2, 2; x<3, 3; x<4, 4; x<5, 5) = 4.0
[mXparser-v.5.2.1] Res 5:  x = 4.5, iff(x<1, 1; x<2, 2; x<3, 3; x<4, 4; x<5, 5) = 5.0

###### Nuget – Package Manager

Install-Package MathParser.org-mXparser -Version 5.2.1

Nuget – .NET CLI

dotnet add package MathParser.org-mXparser --version 5.2.1

Nuget – Package Reference

<PackageReference Include="MathParser.org-mXparser" Version="5.2.1"/>

###### Maven – Dependency

<dependency><groupid>org.mariuszgromada.math</groupid><artifactid>MathParser.org-mXparser</artifactid><version>5.2.1</version></dependency>

implementation 'org.mariuszgromada.math:MathParser.org-mXparser:5.2.1'

implementation("org.mariuszgromada.math:MathParser.org-mXparser:5.2.1")

###### GitHub

git clone https://github.com/mariuszgromada/MathParser.org-mXparser