Python Programm zum Vertauschen zweier Zahlen ohne Verwendung einer dritten Variable

The sections below cover four ways to swap without a temporary variable, plus arithmetic overflow.

In programming languages, swapping means exchanging the values of two variables. The variable might contain a number, string, list or array, object, etc. The general way of swapping Dabei wird eine temporäre Variable verwendet, um Werte zu speichern. Zum Beispiel:

Die allgemeinen Schritte des Tauschsping Die beiden Zahlen lauten:

• Declare a temporary variable C
• Weisen Sie C den Wert von A zu, was bedeutet, dass C = A ist. Jetzt ist C = 20
• Weisen Sie A den Wert von B zu, also A = 30
• Weisen Sie B den Wert von C zu, also ist B = 20, da C den Wert 20 hat.

This is how swapping is done with the help of a temporary variable, and it works for both integer and float numbers.

Tauschen Sie mithilfe der arithmetischen Gleichung

Wie wir wissen, Tauschping means to interchange the content of two objects or fields or variables. Swap using an arithmetic operation means performing the swap using a mathematical equation, i.e., addition and subtraction.

If we are given two numbers and asked to swap without using a temporary variable, then using three arithmetic equations, we can swap the numbers.

Pseudocode für Tauschping numbers using an arithmetic operation:

A = A + B
B = A - B
A = A - B

Let us assume we have two numbers, A = 20 and B = 30.

Bedingung 1: A = A+B

So, the current value of A is 20+30 = 50

Bedingung 2: B = AB

Nun ist B = 50-30 = 20
We can see that we got the value of A in B.

Bedingung 3: A = AB

Schließlich ist A = 50-20 = 30
A hat den Anfangswert von B.

Also haben wir einfach die Nummern vertauscht.

Here is the program to swap two numbers in C/C++:

#include<stdio.h>
int main()
{
	int a, b;
	printf("Enter value of A: ");
	scanf("%d", & a);
	printf("Enter value of B: ");
	scanf("%d", & b);
	printf("A = %d, B = %d", a, b);
	a = a + b;
	b = a - b;
	a = a - b;
	printf("\nNow, A = %d, B = %d", a, b);
}

Ausgang:

Enter value of A: 20
Enter value of B: 30
A = 20 , B = 30
Now, A = 30 , B = 20

Programm in Python:

a = int(input("Enter value of A: "))
b = int(input("Enter value of B: "))
print("A = {} and B = {}".format(a, b))
a = a + b
b = a - b
a = a - b
print("Now, A = {} and B = {}".format(a, b))

Ausgang:

Enter value of A: 20
Enter value of B: 30
A = 20 , B = 30
Now, A = 30 , B = 20

Jetzt in Python, we do not even need to perform arithmetic operations. We can use:

a,b = b,a

Here is a demonstration where a=20, b=30;

Tauschen mit Bitwise XOR OperaDo.

This method is also known as XOR swap. XOR means exclusive OR. We take two bits as inputs to the XOR in this bitwise operation. To get one output from XOR, only one input must be 1. Otherwise, the output will be 0. The following table shows the output for all combinations of input A and B.

We need to know how the XOR operation works to swap two numbers using the bitwise operation. Here is a table for XOR where A and B are the input values.

If two inputs have the same value, then the XOR operation gives 0; otherwise, 1. For this example, we will be using a 3 XOR operation. In most programming languages, XOR is denoted as “^”.

Let us assume A=4 (in Binary = 0100) and B=7 (in Binary, 0111)

Bedingung 1: A = A ^ B

Nun ist A = 0011 (in Binärform).

Bedingung 2: B = A^B

Also B = 0100, was der anfängliche Binärwert von A war.

Bedingung 3: A = A^B

Schließlich ist A = 0111, was der äquivalente Binärwert von B war.

Programmieren in C/C++:

#include<stdio.h>
int main()
{
	int a, b;
	printf("Enter value of A: ");
	scanf("%d", & a);
	printf("Enter value of B: ");
	scanf("%d", & b);
	printf("A = %d, B = %d", a, b);
	a = a ^ b;
	b = a ^ b;
	a = a ^ b;
	printf("\nNow, A = %d, B = %d", a, b);
}

Ausgang:

Enter value of A:4
Enter value of B:7
A=4, B=7
Now, A=7, B=4.

Programm in Python:

a = int(input("Enter value of A: "))
b = int(input("Enter value of B: "))
print("A = {} and B = {}".format(a, b))
a = a ^ b
b = a ^ b
a = a ^ b
print("Now, A = {} and B = {}".format(a, b))

Ausgang:

Enter the value of A:10
Enter the value of B:15
A=10 and B=15
Now, A=15,B=10.

Tausch Numbers mit Bitweiser Arithmetik

This method is the same as the arithmetic method, but we will use bitwise operations such as AND, OR, and complement to perform addition and subtraction. Before going to the steps, let us look over “complement” quickly.

1’s complement means to change all the 0 to 1 and 1 to 0. Let us take an example.

• Let us assume a number 23, a decimal number.
• Converting to Binary gives us 10111. There are only 5 bits, but the computer stores numbers in 8, 16, 32, 64 … bits. So let us add zero in front of the Binary. It will not change the original value of the number. So it will become 00010111.
• As we know, 1’s complement means to change all the 0 to 1 and 1 to 0, so performing 1’s complement over 00010111 gibt 11101000.

This 1’s complement is represented with the “~” symbol in most programming languages. Putting this symbol before any integer values or floating-point values will give the 1’s complement.

Und 2er-Komplement bedeutet das Hinzufügen der binären „1“ zum 1er-Komplement. Wenn wir das 2er-Komplement zur obigen Zahl machen:

• Binär = 00010111
• 1’s complement = 11101000
• Einerkomplement:

11101000

+ 1

11101001

Das Zweierkomplement ist also 2. Dies ist die Binärzahl für -11101001.
Zusammenfassend sieht die Ausführung des Zweierkomplements einer Zahl A wie folgt aus:

2er-Komplement von A = (~A) + 1

Now let us assume A=8 (binary 00001000), B=10 (00001010)

Bedingung 1: A = (A & B) + (A | B)

It is equivalent to A = A + B.

A & B = 00001000 & 00001010 = 00001000

A | B = 00001000 | 00001010 = 00001010

Nun, 00001000 + 00001010 = 00010010 (Dezimal 18)

Also, A = 18

Bedingung 2: B = A + (~B) + 1

It is equivalent to B = A-B

Hier gilt B = A – B

Aus der obigen Diskussion ergibt sich, dass wir, falls wir Unteraufgaben durchführen müssen, …tracBei dieser Kontraktion bilden wir das Zweierkomplement der negativen Zahl und addieren sie dann.

Also -B = ~B + 1

Now, B = 00010010 + (11110101) + 1 = 00001000

Der Wert von B entspricht der Dezimalzahl 8, dem Anfangswert.

Bedingung 3: A = A + (~B) + 1

It is equivalent to A = A-B

Nun ist A = 00010010 + 11110111 + 1

A = 00001010 (entspricht Dezimalzahl 10)

Schließlich erhielt A den Wert von B. Somit ergab sich der Tausch.ping wurde abgeschlossen.

Programmieren in C/C++:

#include<stdio.h>
int main()
{
	int a, b;
	printf("Enter value of A: ");
	scanf("%d", & a);
	printf("Enter value of B: ");
	scanf("%d", & b);
	printf("A = %d, B = %d", a, b);
	a = (a & b) + (a | b);
	b = a + ~b + 1;
	a = a + ~b + 1;
	printf("\nNow, A = %d, B = %d", a, b);
}

Ausgang:

Enter the value of A: 8
Enter the value of B:10
A=8, B=10
Now, A=10, B=8

Programm in Python:

a = int(input("Enter value of A: "))
b = int(input("Enter value of B: "))
print("A = {} and B = {}".format(a, b))
a = (a & b) + (a | b)
b = a + ~b + 1
a = a + ~b + 1
print("Now, A = {} and B = {}".format(a, b))

Ausgang:

Enter the value of A: 25
Enter the value of B: 25
A = 25 and B = 25
Now, A = 25 and B = 25

Was ist ein arithmetischer Überlauf?

The term overflow means exceeding the limit. Arithmetic overflow means that the result of any arithmetic operation exceeds the range or limit of the computer architecture’s number representation. For example, if a number is divided by zero, it becomes infinite, and the computer number system cannot hold it in 32 or 64 bits.

Ganzzahldarstellung in einem 32-Bit-System

Die Folge des arithmetischen Überlaufs kann sein:

• The addition of two positive numbers becomes negative, because the sign bit might become 1, meaning a negative number.
• The addition of two negative numbers becomes positive, because the sign bit might become 0, meaning a positive number.

Häufig gestellte Fragen