Въведение в размяна в PHP
В тази статия ще научим размяната на числа в PHP. Ще научим как да дефинираме размяната, ще научим как да кодираме да заместваме две числа, как да разменяме повече от две числа и три числа и как да разменяме числа с или без временни променливи и други.
Нека първо започнем с определението.
„Размяна в PHP е термин, дефиниран като обмен на стойности.“
Размяна на две числа е процес за обмен на две стойности с помощта или без използване на временна променлива. Надявам се тези примери да са полезни за всички програмисти, които искат да научат концепцията за размяна.
Как да размените две числа в PHP?
Има два начина за размяна на числа. Тези числа съдържат числови стойности.
- Размяна на две числа с временна променлива.
- Размяна на две числа без временна променлива.
Да предположим, че имаме една променлива, притежаваща стойност 10,
число1 = 10;
И другата променлива, притежаваща стойност 20,
число2 = 20;
При размяна на тези две числа резултатът трябва да бъде,
число1 = 20
число2 = 10
Това е възможно с използването на третата временна променлива и без временна променлива. Замяна на две числа може да се извърши с помощта на оператори +, -, *, /.
1. Размяна на две числа с временна променлива
Код:
// Example of swapping of two numbers using a temporary variable <_?php
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Before Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo “ ”;
// declaring temporary variable to be zero
$temp = 0;
// performing swap of numbers
$temp = $num1;
$num1 = $num2;
$num2 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers using a temporary variable
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Before Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo “ ”;
// declaring temporary variable to be zero
$temp = 0;
// performing swap of numbers
$temp = $num1;
$num1 = $num2;
$num2 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers using a temporary variable
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Before Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo “ ”;
// declaring temporary variable to be zero
$temp = 0;
// performing swap of numbers
$temp = $num1;
$num1 = $num2;
$num2 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers using a temporary variable
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Before Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo “ ”;
// declaring temporary variable to be zero
$temp = 0;
// performing swap of numbers
$temp = $num1;
$num1 = $num2;
$num2 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers using a temporary variable
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Before Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo “ ”;
// declaring temporary variable to be zero
$temp = 0;
// performing swap of numbers
$temp = $num1;
$num1 = $num2;
$num2 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo “ ”;
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>
Резултат :
2. Размяна на две числа без временна променлива
Код:
<_?php// Example of swapping of two numbers without using a temporary variable
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statemnt print the variables before swapping two numbers
echo "
"."Swap done without using temparory variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
$num1 = $num1 - $num2;
$num2 = $num1 + $num2;
$num1 = $num2 - $num1;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers without using a temporary variable
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statemnt print the variables before swapping two numbers
echo "
"."Swap done without using temparory variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
$num1 = $num1 - $num2;
$num2 = $num1 + $num2;
$num1 = $num2 - $num1;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers without using a temporary variable
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statemnt print the variables before swapping two numbers
echo "
"."Swap done without using temparory variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
$num1 = $num1 - $num2;
$num2 = $num1 + $num2;
$num1 = $num2 - $num1;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers without using a temporary variable
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statemnt print the variables before swapping two numbers
echo "
"."Swap done without using temparory variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
$num1 = $num1 - $num2;
$num2 = $num1 + $num2;
$num1 = $num2 - $num1;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers without using a temporary variable
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statemnt print the variables before swapping two numbers
echo "
"."Swap done without using temparory variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
$num1 = $num1 - $num2;
$num2 = $num1 + $num2;
$num1 = $num2 - $num1;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>
изход:
3. Размяна на две числа с помощта на функция като list () с масив ()
Код:
<_?php// Example of swapping of two numbers using list() with array()
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Swap done without using predefined functions";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
list($num1, $num2) = array($num2, $num1);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers using list() with array()
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Swap done without using predefined functions";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
list($num1, $num2) = array($num2, $num1);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers using list() with array()
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Swap done without using predefined functions";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
list($num1, $num2) = array($num2, $num1);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers using list() with array()
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Swap done without using predefined functions";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
list($num1, $num2) = array($num2, $num1);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>// Example of swapping of two numbers using list() with array()
// Declaring two variables
$num1 = 100;
$num2 = 200;
// using echo statement print the variables before swapping two numbers
echo "
"."Swap done without using predefined functions";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo " ";
// performing swap of numbers
list($num1, $num2) = array($num2, $num1);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
?>
изход:
Как да размените три числа в PHP?
Има два начина за размяна на числа. Тези числа съдържат числови стойности.
- Размяна на три числа с временна променлива.
- Размяна на три числа без временна променлива.
1. Размяна на три числа с помощта на временна променлива
Сега, когато научихме замяна на две числа, по подобен начин научаваме замяна на три числа сега. Следващият пример демонстрира как временна (temp) променлива се използва за размяна на три числа.
Код:
<_?php// Example of swapping three numbers using temporary variable
// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$temp = $num1;
$num1 = $num2;
$num2 = $num3;
$num3 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>// Example of swapping three numbers using temporary variable
// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$temp = $num1;
$num1 = $num2;
$num2 = $num3;
$num3 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>// Example of swapping three numbers using temporary variable
// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$temp = $num1;
$num1 = $num2;
$num2 = $num3;
$num3 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>// Example of swapping three numbers using temporary variable
// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$temp = $num1;
$num1 = $num2;
$num2 = $num3;
$num3 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>// Example of swapping three numbers using temporary variable
// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$temp = $num1;
$num1 = $num2;
$num2 = $num3;
$num3 = $temp;
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>
изход:
2. Размяна на три числа без използване на временна променлива
Логиката тук е да се изчисли общата сума и да се присвои на променлива $ num1.
И тогава,
изчисли стойността на $ num1, присвои тази стойност на $ num2,
изчисли стойността на $ num2, присвои тази стойност на $ num3,
изчисли стойността на $ num3 и отново присвои тази стойност на $ num1.
Код:
<_?php// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$num1 = $num1 + $num2 + $num3;
$num2 = $num1 - ($num2 + $num3);
$num3 = $num1 - ($num2 + $num3);
$num1 = $num1 - ($num2 + $num3);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$num1 = $num1 + $num2 + $num3;
$num2 = $num1 - ($num2 + $num3);
$num3 = $num1 - ($num2 + $num3);
$num1 = $num1 - ($num2 + $num3);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$num1 = $num1 + $num2 + $num3;
$num2 = $num1 - ($num2 + $num3);
$num3 = $num1 - ($num2 + $num3);
$num1 = $num1 - ($num2 + $num3);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$num1 = $num1 + $num2 + $num3;
$num2 = $num1 - ($num2 + $num3);
$num3 = $num1 - ($num2 + $num3);
$num1 = $num1 - ($num2 + $num3);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>// Declaring three variables
$num1 = 100;
$num2 = 200;
$num3 = 300;
// using echo statement print the variables before swapping three numbers
echo "
"."Swap done without using temporary variable";
echo " ";
echo "
"."Before Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
echo " ";
// performing swap of numbers
//assign first number the total of three numbers
$num1 = $num1 + $num2 + $num3;
$num2 = $num1 - ($num2 + $num3);
$num3 = $num1 - ($num2 + $num3);
$num1 = $num1 - ($num2 + $num3);
//using the echo statement print the variables after swapping the numbers
echo "
"."After Swap";
echo " ";
echo "
"."Value of first number is = ". $num1;
echo "
"."Value of second number is = ". $num2;
echo "
"."Value of third number is = ". $num3;
?>
изход:
заключение
Надявам се тази статия да е полезна за всички програмисти, които желаят да научат размяна на номера. Тази статия има както размяна на две, така и три номера с подходящи примери. Тези примери, ако се практикуват, ще ви помогнат да научите концепцията и също така да запомните логиката.
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