I am making a calculator in java . After entering the string, for calculation, I try to convert it into numbers. In the C language it would be easy, there char is easy to convert to int, but here the string turns into String , and it is not clear how to process it into int . String doesn’t look like an array. If you try to display as: String [1], String [2], String [3] ... – an error. Is it possible, somehow, to split String into characters and convert into a table of corresponding values ​​of type int ? (output characters to numbers)

Answer 1, authority 100%

is very simple:
int num = Integer.parseInt ("12345");

Answer 2, authority 88%

String (String ) in Java is an OOP wrapper over an array of character primitives (char ).

Thus, you can decompose String into a char array using the String # toCharArray () method:

String string = "A string is an array of letters";
char [] charArray = string.toCharArray ();
System.out.println (charArray [0]); // prints "C"

There is also a static method parseInt in the Integer class, which takes a string and outputs a number.

String string = "42";
int awesomeParsedInteger = Integer.parseInt (string);
System.out.println (awesomeParsedInteger); // prints "42"