Úvod do swapovania v PHP
V tomto článku sa naučíme striedanie čísel v PHP. Naučíme sa, ako definujeme swapovanie, naučíme sa kódovať tak, aby si vymenili dve čísla, ako vymeniť viac ako dve čísla a tri čísla a ako vymeniť čísla s dočasnými premennými alebo bez nich a ďalšie.
Začnime najprv definíciou.
„Výmena v PHP je termín definovaný ako výmena hodnôt.“
Výmena dvoch čísel je proces výmeny dvoch hodnôt pomocou dočasnej premennej alebo bez nej. Dúfam, že tieto príklady sú užitočné pre všetkých programátorov, ktorí sa chcú naučiť koncepcii výmeny.
Ako vymeniť dve čísla v PHP?
Existujú dva spôsoby výmeny čísiel. Tieto čísla obsahujú číselné hodnoty.
- Zameniť dve čísla dočasnou premennou.
- Prepínanie dvoch čísel bez dočasnej premennej.
Predpokladajme, že máme jednu premennú s hodnotou 10,
číslo 1 = 10;
A druhá premenná má hodnotu 20,
číslo 2 = 20;
Výsledkom výmeny týchto dvoch čísel by malo byť,
number1 = 20
číslo 2 = 10
To je možné s použitím tretej dočasnej premennej a tiež bez dočasnej premennej. Prepínanie dvoch čísel je možné pomocou operátorov +, -, *, /.
1. Výmena dvoch čísel za dočasnú premennú
kód:
// 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;
?>
Výstup :
2. Výmena dvoch čísel bez dočasnej premennej
kód:
<_?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;
?>
Výkon:
3. Prepínanie dvoch čísel pomocou funkcie ako list () s array ()
kód:
<_?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;
?>
Výkon:
Ako vymeniť tri čísla v PHP?
Existujú dva spôsoby výmeny čísiel. Tieto čísla obsahujú číselné hodnoty.
- Zameniť tri čísla dočasnou premennou.
- Zamieňanie troch čísel bez dočasnej premennej.
1. Výmena troch čísel pomocou dočasnej premennej
Teraz, keď sme sa naučili striedanie dvoch čísel, podobne sa naučíme striedanie troch čísel. Nasledujúci príklad ukazuje, ako sa dočasná (dočasná) premenná používa na výmenu troch čísel.
kód:
<_?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;
?>
Výkon:
2. Výmena troch čísel bez použitia dočasnej premennej
Logika tu spočíva v vypočítaní celkovej sumy a jej priradení k premennej $ num1.
A potom,
vypočítajte hodnotu $ num1, priraďte túto hodnotu $ num2,
vypočítajte hodnotu $ num2, priraďte túto hodnotu $ num3,
vypočítajte hodnotu $ num3 a túto hodnotu znovu priraďte k $ num1.
kód:
<_?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;
?>
Výkon:
záver
Dúfam, že tento článok je užitočný pre všetkých programátorov, ktorí sa chcú naučiť zamieňať čísla. V tomto článku sú vymenené dve a tri čísla s príslušnými príkladmi. Tieto príklady, ak sa používajú, vám pomôžu osvojiť si tento koncept a pomôžu vám spomenúť si aj na logiku.
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