In C++, you can create template functions, which are functions that are parameterized by one or more types. Template functions allow you to write a single function that can be used with different types, without having to write separate functions for each type.

Here's an example of a template function that finds the maximum value in an array of values:

template <typename T>
T max_value(T* values, int size) {
    T max = values[0];
    for (int i = 1; i < size; i++) {
        if (values[i] > max) {
            max = values[i];
        }
    }
    return max;
}

In this example, we define a function called max_value that is parameterized by a single type T. The function takes two arguments: an array of values of type T, and an integer size that specifies the number of elements in the array. The function returns the maximum value in the array.

To use the max_value function with a particular type, you can call it with that type:

int int_values[] = {1, 2, 3, 4};
int max_int = max_value<int>(int_values, 4);

double double_values[] = {1.1, 2.2, 3.3, 4.4};
double max_double = max_value<double>(double_values, 4);

In this example, we call the max_value function with two different types (int and double). In each case, we specify the type parameter in angle brackets (<...>) immediately following the function name.

You can also use type inference to avoid specifying the type parameter explicitly, as in the following example:

int int_values[] = {1, 2, 3, 4};
int max_int = max_value(int_values, 4);

double double_values[] = {1.1, 2.2, 3.3, 4.4};
double max_double = max_value(double_values, 4);

In this example, the compiler infers the type parameter from the type of the argument passed to the function.

In summary, template functions in C++ allow you to write generic functions that can be used with different types. To define a template function, you use the template keyword followed by the list of type parameters in angle brackets (<...>), and then use the type parameter name(s) wherever you would normally use a type in the function definition. To use a template function, you call it with the desired type(s) and then use the resulting function as you would any other function.