Introduktion til swapping i PHP
I denne artikel lærer vi udveksling af tal i PHP. Vi lærer, hvordan vi definerer bytte, vi lærer, hvordan man koder for at bytte to numre, hvordan man bytter mere end to tal og tre numre, og hvordan man bytter tal med eller uden midlertidige variabler og mere.
Lad os starte med definitionen først.
"At bytte i PHP er et udtryk defineret som udveksling af værdier."
Udskiftning af to tal er en proces til udveksling af to værdier ved hjælp af eller uden brug af en midlertidig variabel. Jeg håber, at disse eksempler er nyttige for alle de programmører, der ønsker at lære begrebet swapping.
Sådan skiftes to numre i PHP?
Der er to måder at skifte tal på. Disse tal indeholder numeriske værdier.
- Byt to numre med en midlertidig variabel.
- Byt to numre uden en midlertidig variabel.
Antag, at vi har en variabel, der har en værdi 10,
nummer1 = 10;
Og den anden variabel, der har en værdi 20,
nummer2 = 20;
Ved udskiftning af disse to numre skal resultatet være,
nummer1 = 20
nummer2 = 10
Dette er muligt ved brug af den tredje midlertidige variabel og uden en midlertidig variabel også. Udskiftning af to numre kan udføres ved hjælp af +, -, *, / operatorer.
1. Skift to numre med en midlertidig variabel
Kode:
// 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;
?>
Output :
2. Skift to numre uden midlertidig variabel
Kode:
<_?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;
?>
Produktion:
3. Udskiftning af to numre ved hjælp af en funktion som liste () med matrix ()
Kode:
<_?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;
?>
Produktion:
Sådan udskiftes tre numre i PHP?
Der er to måder at skifte tal på. Disse tal indeholder numeriske værdier.
- Byt tre numre med en midlertidig variabel.
- Byt tre numre uden en midlertidig variabel.
1. Skift tre numre vha. Midlertidig variabel
Nu hvor vi har lært at bytte af to tal, på en lignende måde lærer vi at bytte af tre numre nu. Følgende eksempel viser, hvordan en midlertidig (temp) variabel bruges til at bytte tre numre.
Kode:
<_?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;
?>
Produktion:
2. Skift tre numre uden at bruge en midlertidig variabel
Logikken her er at beregne den samlede sum og tildele den til en $ num1-variabel.
Og så,
beregne værdien af $ num1, tildel denne værdi til $ num2,
beregne værdien af $ num2, tildel denne værdi til $ num3,
beregne værdien af $ num3, og tildel denne værdi til $ num1 igen.
Kode:
<_?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;
?>
Produktion:
Konklusion
Jeg håber, at denne artikel er nyttig for alle de programmører, der ønsker at lære at udveksle tal. Denne artikel har både swappinger af to og tre numre med passende eksempler. Disse eksempler, hvis de praktiseres, hjælper dig med at lære konceptet og hjælpe dig med at huske logikken også.
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