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BigInteger compareTo() Method in Java
• Last Updated : 04 Dec, 2018

The java.math.BigInteger.compareTo(BigInteger value) method Compares this BigInteger with the BigInteger passed as the parameter.

Syntax:

`public int compareTo(BigInteger val)`

Parameter: This method accepts a single mandatory parameter val which is the BigInteger to compare with BigInteger object.

Returns: This method returns the following:

• 0: if the value of this BigInteger is equal to that of the BigInteger object passed as a parameter.
• 1: if the value of this BigInteger is greater than that of the BigInteger object passed as a parameter.
• -1: if the value of this BigInteger is less than that of the BigInteger object passed as a parameter.

Examples:

```Input: BigInteger1=2345, BigInteger2=7456
Output: -1
Explanation: BigInteger1.compareTo(BigInteger2)=-1.

Input: BigInteger1=9834, BigInteger2=7456
Output: 1
Explanation: BigInteger1.compareTo(BigInteger2)=1.
```

Example 1: Below programs illustrate compareTo() method of BigInteger class when both BigIntegers are equal

 `// Java program to demonstrate ``// compareTo() method of BigInteger`` ` `import` `java.math.BigInteger;`` ` `public` `class` `GFG {`` ` `    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Creating 2 BigInteger objects``        ``BigInteger b1, b2;`` ` `        ``b1 = ``new` `BigInteger(``"321456"``);``        ``b2 = ``new` `BigInteger(``"321456"``);`` ` `        ``// apply compareTo() method``        ``int` `comparevalue = b1.compareTo(b2);`` ` `        ``// print result``        ``if` `(comparevalue == ``0``) {`` ` `            ``System.out.println(``"BigInteger1 "``                               ``+ b1 + ``" and BigInteger2 "``                               ``+ b2 + ``" are equal"``);``        ``}``        ``else` `if` `(comparevalue == ``1``) {`` ` `            ``System.out.println(``"BigInteger1 "` `+ b1 + " ``                ``is greater than BigInteger2 " + b2);``        ``}``        ``else` `{`` ` `            ``System.out.println(``"BigInteger1 "` `+ b1 + " ``                ``is lesser than BigInteger2 " + b2);``        ``}``    ``}``}`
Output:
```BigInteger1 321456 and BigInteger2 321456 are equal
```

Example 2: when BigInteger1 is greater than BigInteger2

 `// Java program to demonstrate ``// compareTo() method of BigInteger`` ` `import` `java.math.BigInteger;`` ` `public` `class` `GFG {`` ` `    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Creating 2 BigInteger objects``        ``BigInteger b1, b2;`` ` `        ``b1 = ``new` `BigInteger(``"654321"``);``        ``b2 = ``new` `BigInteger(``"321456"``);`` ` `        ``// apply compareTo() method``        ``int` `comparevalue = b1.compareTo(b2);`` ` `        ``// print result``        ``if` `(comparevalue == ``0``) {`` ` `            ``System.out.println(``"BigInteger1 "` `+ b1 + " ``                ``and BigInteger2 ``" + b2 + "` `are equal");``        ``}``        ``else` `if` `(comparevalue == ``1``) {`` ` `            ``System.out.println(``"BigInteger1 "` `+ b1 + "``                ``is greater than BigInteger2 " + b2);``        ``}``        ``else` `{`` ` `            ``System.out.println(``"BigInteger1 "` `+ b1 + " ``                ``is lesser than BigInteger2 " + b2);``        ``}``    ``}``}`
Output:
```BigInteger1 654321 is greater than BigInteger2 321456
```

Example 3: When BigInteger1 is lesser than BigInteger2

 `// Java program to demonstrate ``// compareTo() method of BigInteger`` ` `import` `java.math.BigInteger;`` ` `public` `class` `GFG {`` ` `    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Creating 2 BigInteger objects``        ``BigInteger b1, b2;`` ` `        ``b1 = ``new` `BigInteger(``"321456"``);``        ``b2 = ``new` `BigInteger(``"564321"``);`` ` `        ``// apply compareTo() method``        ``int` `comparevalue = b1.compareTo(b2);`` ` `        ``// print result``        ``if` `(comparevalue == ``0``) {`` ` `            ``System.out.println(``"BigInteger1 "` `+ b1 + " ``                 ``and BigInteger2 ``" + b2 + "` `are equal");``        ``}``        ``else` `if` `(comparevalue == ``1``) {`` ` `            ``System.out.println(``"BigInteger1 "` `+ b1 + " ``                  ``is greater than BigInteger2 " + b2);``        ``}``        ``else` `{`` ` `            ``System.out.println(``"BigInteger1 "` `+ b1 + "``                 ``is lesser than BigInteger2 " + b2);``        ``}``    ``}``}`
Output:
```BigInteger1 321456 is lesser than BigInteger2 564321
```

Reference:
BigInteger CompareTo() Docs

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