Programming Fundamentals/Conditions/PHP

conditions.php

```<?php

// This program asks the user to select Fahrenheit or Celsius conversion
// and input a given temperature. Then the program converts the given
// temperature and displays the result.
//
// References:
//     https://www.mathsisfun.com/temperature-conversion.html
//     https://en.wikibooks.org/wiki/PHP_Programming

function to_celsius()
{
echo "Enter Fahrenheit temperature:\n";
\$c = (\$f - 32) * 5 / 9;
echo \$f . "° Fahrenheit is " . \$c . "° Celsius";
}

function to_fahrenheit()
{
echo "Enter Celsius temperature:";
\$f = \$c * 9 / 5 + 32;
echo \$c . "° Celsius is " . \$f . "° Fahrenheit";
}

function if_else()
{
printf("Enter F to convert to Fahrenheit or C to convert to Celsius:");

if(\$choice == 'C' || \$choice == 'c')
{
to_celsius();
}
else if(\$choice == 'F' || \$choice == 'f')
{
to_fahrenheit();
}
else
{
echo "You must enter C to convert to Celsius or F to convert to Fahrenheit!";
}
}

function switch_case()
{
printf("Enter F to convert to Fahrenheit or C to convert to Celsius:");

switch(\$choice)
{
case 'C':
case 'c':
to_celsius();
break;
case 'F':
case 'f':
to_fahrenheit();
break;
default:
echo "You must enter C to convert to Celsius or F to convert to Fahrenheit!";
}
}

function main()
{
if_else();
switch_case();
}

main();

?>
```

Try It

Copy and paste the code above into one of the following free online development environments or use your own PHP compiler / interpreter / IDE.