# PHP Tutorial - PHP Integer

Integers hold whole numbers, either positive or negative, such as 1, -20, 12345,etc. The limit of integer is between -2147483647 and 2147483647. The integer numbers outside the range are automatically converted to floats.

The following code adds two integer values together in PHP.

``````
<?php
\$var1 = 5;
\$var2 = 2;
print "\$var1 plus \$var2 equals \$answer.";
?>
``````

The code above generates the following result.

## PHP integer Literal

We may specify integers in hexadecimal (base 16) or octal (base 8). The octal number system only uses the digits 0 to 7. hexadecimal uses 0 to 9, then A, B, C, D, E, and F.

To specify number in octal, we must precede it with a 0 (zero).

``````
<?PHP
\$octalnum = 06331;
print \$octalnum;
?>
``````

The code above generates the following result.

To specify a number in hexadecimal, precede it with `0x`.

``````
<?PHP
\$hexnum = 0x44;
print \$hexnum;
?>
``````

The code above generates the following result.

## Example - Integer literal

The following code uses different integer literals to assign value to integers.

``````
<?PHP//from ww  w.j  av a 2s.c o m
\$a = 1234; # decimal number
print(\$a);
print("\n");
\$a = -123; # a negative number
print(\$a);
print("\n");
\$a = 0123; # octal number (equivalent to 83 decimal)
print(\$a);
print("\n");
\$a = 0x12; # hexadecimal number (equivalent to 18 decimal)
print(\$a);
print("\n");
?>
``````

The code above generates the following result.

## Float

Floats hold fractional numbers as well as very large integer numbers, such as 4.2, 1.00000001, and 123123123123000.

Floating-point numbers are called real numbers or just floats.

## Float Literal

We may also specify an exponent with your float, i.e., 3.14159e4 is equal to 31415.9.

``````
<?PHP
\$a = 1.234;
print (\$a);
print ("\n");
\$a = 1.2e3;
print (\$a);
?>
``````

The code above generates the following result.

## Example - floating-point arithmetic

Here are some examples of floating-point arithmetic:

``````
<?PHP//from   w  w  w .  ja  v a2  s.co  m
\$a = 1.132324;
print(\$a);
\$b = \$a + 1.9;
print(\$b);
\$b = \$a + 1.0;
print(\$b);
\$c = 1.1e15;
print(\$c);
\$d = (0.1+0.7) * 10;
print(\$d);
?>
``````

The code above generates the following result.

## Example - Calculate the area of a circle of given radius

Calculate the area of a circle of given radius

``````
<?php//  w  w  w  . j a  va2s. co m