C++ Max

C++ max() Function

In C++, the max() function is very useful for programmers to find the largest element from a set of elements. There are three ways in which we can compare elements using the max() function, depending on how the elements are passed as an argument to the max() function.

• Passing two elements onto its argument to compare - In this case, the larger value is returned. The first one is returned if both are equal. Example: std::max(5, 20)

• Using a binary function - A binary function is a pre-defined function by the programmer which takes two inputs. The binary function is passed as an argument to the max() function. It compares the two inputs and returns true or false based on the condition defined by the programmer. Here, we have declared a binary function as cmp. Example: std::max( x , y , cmp )

• From a list - In this case, the max() function in C++ finds the largest element in a given list. If there is more than one larger element in the list, it returns the first element. Example: max({15 , 2, -8 , 6}) or Example: max({10 , 5 , 37 , -13}, cmp)

Here, we have declared a binary function as cmp.

3 Versions of C++ max() Function

1. For comparing elements, using "< "

The max() function in C++ is used to find the largest of the numbers passed to it as arguments. The C++ max() function compares the numbers using the less operator.

Syntax

In this case, a and b are the values to be compared. It returns the larger value of the two.

The C++ max() function uses fewer operators to compare the values by default. Alternatively, you can specify your comparison operator or function if you don't want it to work with <.

Code

Output

In the above example, in line 7, we use the max() function to find the larger value between 2 and 5. If you see the other lines, we can also compare integers, floating point numbers, characters, and strings using ASCII values.

In the case of two similar numbers, the max() function returns the first one.

Time Complexity - O(1)

Auxiliary Space - O(1)

Parameters of C++ max() Function

Below are the parameters that can be passed to max().

Syntax:

a: It is the first number to be compared.

b: It is the second number to be compared with the first one.

Two or more variables with the same data type can be passed as parameters for comparison.

comparator: It is a binary function that takes two variables as parameters and returns a bool value.

Return Value of C++ max() Function

In the max() function, a variable of the same data as inputs is returned, and it is the largest among all the values passed.

Exceptions of C++ max() Function

When any comparison throws an error, the max() method also throws. Invalid arguments cause undefined behavior.

In the above example, we pass two values of different data types into the max() function, which is not a valid step. Similarly, the next comparison between a character and an integer cannot be compared.

Therefore, in the max() function, you must pass two variables of the same data type.

How does the C++ max() Function work?

std::max is a template function (defined in the header <algorithm>) that can be used to compare primitive datatypes. For non-primitive data types, the programmer can define a comparison function with the max() function. The less operator is used by default to compare the values. Alternatively, you can specify your comparison operator or function if you don't want it to work with <.

C++ max() function can therefore be used on primitive data types, i.e., floats, doubles, and long doubles since they provide less than the operator.

Uses of C++ max() Function

In the case of different types of arguments, std::max is safer because it requires explicit conversion. A 64-bit int, for example, can't be accidentally converted to a 64-bit float by the compiler. As a result, templates should be used as a default.

C++ max functions are type-specific, so you should prefer them if you're using C++. They provide type safety and prevent mixed-type comparisons, which can sometimes be undesirable.

Examples of C++ max() Function

Example 1

Using the max() function with the absolute values returns the maximum of the two values irrespective of their signs. Thus, the program returns -6 in the code below.

Code:

Output

Example 2

In this case, you can find the maximum value from an array using the below code.

Code:

Output

Explanation

We need to traverse the array elements using the max() function to find the maximum value from an array. Each element has to be compared with a pre-defined variable by the user. At the end of the array, you'll get the maximum element among all the array elements.

Related Functions in C++

• strcmp() in C++ - In strcmp(), the two strings are compared lexicographically, starting from the first character and continuing until the two strings have the same characters, or NULL characters are encountered.
• floor() in C++ - When used in C++, the floor() method returns the largest integer number that is less than or equal to the provided parameter.

Read More:

• Data Types in C++.
• C++ Functions.