int i, j, k; char c, ch; float f, salary; double d; For Constant: const int LENGTH = 10;
var helloText = "Hello, SwitchToSwift”
The declaration uses the keyword var which stands for variable. After that, we give the variable a name hello text. Then you have the equal sign, known as the assignment operator = and then you have a string that needs to be enclosed in double quotation marks.
Declaring a constant uses the let keyword. In this case, we are going to define a constant g;
let g = 9.8
Constant values cannot be changed after they are declared.
so if ,we try to change the value of our constant π we’d get an error message:
let g = 9.8 g =9.2
//error: cannot assign to ‘let’ value ‘g’ g = 9.8
You can even declare multiple variables on the same line by using a comma separator.
var x = 5, y = 6, z = 7
Now what if we don’t want x to store number values, we want it to store a String type. This is when we use what’s called explicit type declarations.
var x : String
Now if we try to put a number to this variable we gonna get an error because we gave type as String
x = 5
// error: type ‘String’ does not conform to protocol IntegerLiteralConvertible’