When to use float and integer?

Answer 1

float when you need a decimal. integer when you need a whole number

example
integer for counting number of people (you cant have a fraction of a person)
float for calculating area of a circle

also, i prefer using double instead of float

Answer 2

yea you can use int instead of float, as 10 and 20 are whole numbers

Answer 3

it should work. try it and check again for errors

Answer 4

float a =10;
float b = 20;
float c = a+b;
console.WriteLine (c);
console.ReadKey ( );
can i use int instead of float here??
but if i do so it's not working

Answer 5

yeah working thank u so much :)