For a long time ago, the software development follows a simple pattern. This pattern help you for know general syntax or parts when you develop.
I don’t want to talk about an specific programming language, you need to understand this and apply on your own logic programming, see more examples and follow more guides in your specific programming language because this should change between programming languages.
Maybe you need to learn this first. This is used in multiple programming languages and have a little differences but the names and how to use are relatively different.
String are used for text of alphabetical. When you write text in your system, probably you are using Strings. Usually are declared with double quote (“”) or only one quote (’’), then the text you should introduce it between the quotes.
"your text value as String"
'Another value as String'
Multiples systems are used for calculate complicated operations. This only have a integer numbers.
This have sizes what are the limit of the int number, it depending of the programming language and your integer value.
12345
If you need to use decimal numbers follow the next type.
Probably, in some operations or decimal numbers, this is your best option. Float and double are two types what you need to know, those saves decimal values.
Sometimes when you get percentage, divide two numbers or get root or other operations, you should get and decimal value or total.
The difference between float and double is, float contains less decimals numbers than double.
14.3333 //Float
55.99999999 // Double