# isunordered() function in C++

The isunordered() function is defined in <cmath.h> and checks whether the value of first argument can be meaningfully compared with the second argument. If the first argument cannot be meaningfully compared with the second argument (i.e one or both are NAN), it return 1 otherwise 0.

Syntax:

`bool isunordered(float x, float y);`

or

`bool isunordered(double x, double y);`

Parameters: It takes two values x and y i.e values to check whether they are unordered.

Returns: It returns 1 if the value of x or y are NAN, Otherwise it returns 0.

Below programs illustrate the isunordered() function in C++:

Example 1:-

 `// c++ program to demonstrate ` `// example of isunordered() function. ` ` `  `#include ` `using` `namespace` `std; ` ` `  `int` `main() ` `{ ` `  ``float` `x=6.3; ` `  ``float` `y=``sqrt``(-9); ` ` `  `  ``cout<<``"The value of x is= "``<< x << endl; ` `  ``cout<<``"The value of y is= "``<< y << endl; ` ` `  `  ``//Now it return whether x or y are unordered values or not ` `  ``cout<<``"isunordered(x, y) = "``<

Output:
```The value of x is= 6.3
The value of y is= -nan
isunordered(x, y) = 1
```

Explanation: In the example 1 the value of y is NAN thats why function returns 1.

Example 2:-

 `// c++ program to demonstrate ` `// example of isunordered() function. ` ` `  `#include ` `using` `namespace` `std; ` ` `  `int` `main() ` `{ ` `  ``float` `x=4.6; ` `  ``float` `y=9.2; ` ` `  `  ``cout<<``"The value of x is= "``<< x << endl; ` `  ``cout<<``"The value of y is= "``<< y << endl; ` ` `  `  ``//Now it return whether x or y are unordered values or not ` `  ``cout<<``"isunordered(x, y) = "``<

Output:
```The value of x is= 4.6
The value of y is= 9.2
isunordered(x, y) = 0
```

Explanation: In the example 2 the value of x and y are not NAN thats why the function returns 0.

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