Wednesday, June 19, 2019 00:58

Int variable type

A variable is a name that the compiler assigns to one or more memory location(s). When you declare a variable in a program, you have to specify its type and name. The type of a variable specifies the kind of values that the variable can store and the set of operations that the program can execute on variables. For the int variable type, the C# compiler usually allocates 32 bits (4 bytes). The int variable type can store values from -2,147,483,648 to 2,147,483,647. The following image illustrates how an int variable type is represented in C#: Int variable types are integer numbers. They do not have a fractional part, like real numbers (represented in floating point). If you assign to an int variable a value outside the  -2,147,483,648 to 2,147,483,647 range, you will get what programming calls overflowand the assigned value will be wrong.

EXERCISES
1. Declare two variables of type int. Assign to them values 5 and 10 respectively. Exchange (swap) their values and print them.

Solution

Use third temporary variable for exchanging the variables:

To swap integer variables other solutions exist which do not use a third variable. For example, if we have two integer variables a and b:

You might also use the XOR swap algorithm for exchanging integer values: http://en.wikipedia.org/wiki/XOR_swap_algorithm.

2. The gravitational field of the Moon is approximately 17% of that on the Earth. Write a program that calculates the weight of a man on the moon by a given weight on the Earth.

Solution

Guidelines: Read the number from the console, multiply it by 0.17 and print it.

3. Write a program that takes as input a four-digit number in format abcd (e.g. 2011) and performs the following actions:
– Calculates the sum of the digits (in our example 2+0+1+1 = 4).
– Prints on the console the number in reversed order: dcba (in our example 1102).
– Puts the last digit in the first position: dabc (in our example 1201).
– Exchanges the second and the third digits: acbd (in our example 2101).

Solution

Guidelines: To get the individual digits of the number you can divide by 10 and take the remainder of the division by 10 four times.