# isgreater() in C/C++

In C++, isgreater() is a predefined function used for mathematical calculations. math.h is the header file required for various mathematical functions.

isgreater() function used to check whether the 1st argument given to the function is greater than the 2nd argument given to the function or not. Means if a is the 1st argument and b is the 2nd argument then it check whether a>b or not.

Syntax:

```bool isgreater(a, b)
Parameters:
a, b => These two are the parameters whose value we want to compare.
Result:
The function will return the true if a>b else it returns false.

Error:
No error occurs with this function.
Exception:
If a or b or both is NaN,
then the function raised an exception and return false(0).
```

 `// CPP code to illustrate ` `// the exception of function ` `#include ` `using` `namespace` `std; ` ` `  `int` `main() ` `{ ` `    ``// Take any values ` `    ``int` `a = 5; ` `    ``double` `f1 = nan(``"1"``); ` `    ``bool` `result; ` ` `  `    ``// Since f1 value is NaN so ` `    ``// with any value of a, the function ` `    ``// always return false(0) ` `    ``result = isgreater(f1, a); ` `    ``cout << f1 << ``" isgreater than "` `<< a ` `         ``<< ``": "` `<< result; ` ` `  `    ``return` `0; ` `} `

Output:

```nan isgreater than 5: 0
```

Example:

• Program:

 `// CPP code to illustrate ` `// the use of isgreater function ` `#include ` `using` `namespace` `std; ` ` `  `int` `main() ` `{ ` `    ``// Take two any values ` `    ``int` `a, b; ` `    ``bool` `result; ` `    ``a = 5; ` `    ``b = 8; ` ` `  `    ``// Since 'a' is not greater ` `    ``// than 'b' so answer ` `    ``// is false(0) ` `    ``result = isgreater(a, b); ` `    ``cout << a << ``" isgreater than "` `<< b ` `         ``<< ``": "` `<< result << endl; ` ` `  `    ``char` `x = ``'d'``; ` ` `  `    ``// Since 'd' ascii value is greater ` `    ``// than b vaiable so answer ` `    ``// is true(1) ` `    ``result = isgreater(x, b); ` `    ``cout << x << ``" isgreater than "` `<< b ` `         ``<< ``": "` `<< result; ` ` `  `    ``return` `0; ` `} `

Output:

```5 isgreater than 8: 0
d isgreater than 8: 1
```
• Note: Using this function you can compare any data type with any other data type as well.

Application

• This function can be used in any comparison based sorting algorithm. Let’s use it in bubble sort:

 `// CPP code to illustrate the  ` `// use of isgreaterequal function ` `#include ` `using` `namespace` `std; ` ` `  `int` `main() ` `{ ` `    ``// taking inputs ` `    ``int` `arr[] = { 5, 2, 8, 3, 4 }; ` `    ``int` `n = ``sizeof``(arr) / ``sizeof``(arr); ` ` `  `    ``for` `(``int` `i = 0; i < n - 1; i++)  ` `    ``{ ` `        ``for` `(``int` `j = 0; j < n - i - 1; j++)  ` `        ``{ ` `            ``if` `(isgreater(arr[j], arr[j + 1]))  ` `            ``{ ` `                ``int` `k = arr[j]; ` `                ``arr[j] = arr[j + 1]; ` `                ``arr[j + 1] = k; ` `            ``} ` `        ``} ` `    ``} ` ` `  `    ``cout << ``"Sorted array: "``; ` `    ``for` `(``int` `i = 0; i < n; i++) { ` `        ``cout << arr[i] << ``", "``; ` `    ``} ` `    ``return` `0; ` `} `

Output:

```Sorted array: 2, 3, 4, 5, 8,
```

My Personal Notes arrow_drop_up Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Article Tags :
Practice Tags :

Be the First to upvote.

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.