Intergers
Intergers are numbers from 0 to 9 that can be negative or positive but cannot contain decimal places. Before you make a variable in a program you must declare it (int, followed by the variable name). Each data type takes up take up memory sapce. Intergers occupy 2 bytes of memory (16 bits) which means intergers can take values from -32,768 to 32,767. If you enter a number larger or lower than the limits, the program will store it as something else. If you want the variable to be a value that exceeds the 2 bytes, you can use qualifers to double the storage space for a variable. The four qualifiers in C++ are:
short int - Same as signed.
long int - Occupy 4 bytes (32 bits) positive and negative values.
signed int - The same as int (variable name);
unsigned int - Can hold a value up to 65,535 but a negative value cannot be used.
(the bits and bytes listed above may differ depending on the compiler you are using)
Floating Point
Floating types can have a decimal place, intergers, and exponents. Floating point will store 6 digits after the decimal point and will round up if any more are added. Examples of floating piont variables:
19
3.5576
0.4
4e7 (4 to the exponent of 7)
Exponents must be intergers (not decimals). Floating points are declared as follows: float (variable name);
Double
The same as a floating point except it can hold values up to 10e308 (10 to the exponent of 308). It is declared like this: double (variable name);
Character
Characters can be anything on the keyboard (numbers and lettere). They will only store one character in memory so you cannot enter a two didgit number. This is how it is declared: char (variable name); For obtaining a certain response from your program using a character variable, you need to use a switch statement. An if or else or else if statement will not work in this case. To understand this, I think it is best to take a look at how it is written and do some trial programs yourself until you get it. There is a program illustrating a switch at the bottom of this page.
Boolean Type
This data type accepts true and false values only. Here is a little example:
cout << "enter a letter";
cin >> letter;
switch (letter) {
case 'a':
case 'e':
case 'i':
case 'o':
case 'u':
cout << "you chose a vowel\n";
break;
default:
cout << "you did not choose a vowel\n";
}
cout << "one is greater than two\n";
cin >> test;
if (test == false) {
cout << "correct\n";
}
if (test == true) {
cout << "wrong\n";
}