How can I convert a String variable to a primitive int in Java

Question

I want to convert a String(having just numbers) to int. For Example: "100" to be converted to a numeric 100. So that I can perform Arithmetic operations on it.

Answer 1

You can convert a String to int by using a function:

int num= Integer.parseInt(string);

For Example:

String s="100";
int i=Integer.parseInt(s);

You can convert a String to Integer by using a function:

int num=Integer.valueOf(string);

String s="100";
int i=Integer.valueOf(s);

Answer 2

 Here are two ways illustrating this:

Integer x = Integer.valueOf(str);// orint y = Integer.parseInt(str);

There is a slight difference between these methods:

• valueOf returns a new or cached instance of java.lang.Integer
• parseInt returns primitive int.

The same is for all cases: Short.valueOf/parseShort, Long.valueOf/parseLong, etc.