# Java Program to Get the Maximum Element From a Vector

• Last Updated : 07 Jul, 2021

Prerequisite: Vectors in Java

Why We Use Vector?

Till now, we have learned two ways for declaring either with a fixed size of array or size enter as per the demand of the user according to which array is allocated in memory.

```int Array_name[Fixed_size] ;
int array_name[variable_size] ;```

Both ways we land up wasting memory so in order to properly utilize memory optimization vectors are introduced.

• Dynamic Size
• Rich Library Functions
• Easy To Know Size
• No Need To Pass Size
• Can be returned from a function
• By default initializes with default values

Rich Library Functions Includes

1. Find An Element
2. Erase An Element
3. Insert An Element

Here, we use rich library functions to get a maximum element.

Note: Arrays are always passed as a pointer in arrays so another parameter you must pass the size of the array but that is not required in the case of vectors.

Syntax :

In the case of Arrays

`type function_Name(type arrayName[], type sizeOfArray) ;`

In the case of Vectors

`type function_Name(vector<type> vectorName) ;`

Considering An Example given a vector, the task is to find the maximum element.

Examples:

Input: v1={1,2,3,4,5}

Output: 5

Input: v2={7,50,0,67,98}

Output: 98

### Method 1: Using a Predefined Function

• First, we will initialize a vector lets say v, then we will store values in that vector.
• After that, we will call the predefined method called max() defined in class java.util.Collections.
• Print the max element.

Below is the implementation of the above approach.

## Java

 `// Java Program to find maximum element``// in a vector using predefined method`` ` `import` `java.io.*;` `// Importing Vector Class``import` `java.util.Collections;` `// Importing Vector Class``import` `java.util.Vector;` `class` `GFG {``  ` `    ``// Main Method``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// initializing a Vector``        ``Vector v = ``new` `Vector();``      ` `        ``// adding values to the Vector``        ``v.add(``7``);``        ``v.add(``50``);``        ``v.add(``0``);``        ``v.add(``67``);``        ``v.add(``98``);``      ` `        ``// finding the largest element``        ``int` `n = Collections.max(v);``      ` `        ``// printing the largest element``        ``System.out.println(``            ``"The maximum value present in Vector is : "``            ``+ n);``    ``}``}`

Output :

`The maximum value present in Vector is : 98`

Worst Case Time Complexity: O(n) where n is the number of elements present in the vector.

### Method 2: Comparing each element present in Vector

• First, we will initialize a vector lets say v, then we will store values in that vector.
• Next, we will take a variable, let us say maxNumber and assign the minimum value possible.
• Traverse till the end of vector and compare each element of a vector with maxNumber.
• If the element present in the vector is greater than maxNumber, then update maxNumber to that value.
• Print maxNumber.

Below is the implementation of the above approach.

## Java

 `// Java program to find largest element``// present in Vector via comparison` `import` `java.io.*;` `// Importing Vector Class``import` `java.util.Vector;` `// Importing Iterator Class``import` `java.util.Iterator;` `class` `GFG {``  ` `    ``// Main Method``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// initializing vector of Integer type``        ``Vector v = ``new` `Vector();``      ` `        ``// Adding elements in vector``        ``v.add(``1``);``        ``v.add(``2``);``        ``v.add(``3``);``        ``v.add(``4``);``        ``v.add(``5``);``      ` `        ``// Assigning min value possible``        ``int` `maxValue = Integer.MIN_VALUE;``      ` `        ``// Creating an iterator to traverse through vector``        ``// in the beginning itr will point to index just``        ``// before first element``        ``Iterator itr = v.iterator();``      ` `        ``// See if there is any next element``        ``while` `(itr.hasNext())``        ``{``            ``// Moving iterator to next element``            ``int` `element = (Integer)itr.next();` `            ``// Comparing if element is larger than maxValue``            ``if` `(element > maxValue)``            ``{``                ``// Update maxValue``                ``maxValue = element;``            ``}``        ``}``      ` `        ``// Print maxVaue``        ``System.out.println(``            ``"The largest element present in Vector is : "``            ``+ maxValue);``    ``}``}`

Output :

`The largest element present in Vector is : 5`

Time Complexity: O(n) where n is the number of elements present in the vector.

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