- C Programming Examples
- C Programming Examples
- C Print Hello World
- C Get Input from User
- C Print Integer
- C Add Two Numbers
- C Add Subtract Multiply Divide
- C Add n Numbers
- C Area Perimeter of Square
- C Area Perimeter of Rectangle
- C Area Circum of Circle
- C Fahrenheit to Celsius
- C Celsius to Fahrenheit
- C Inches to Centimeters
- C Kilogram to Gram
- C Reverse a Number
- C Swap Two Numbers
- C Interchange Numbers
- C Print ASCII Value
- C Print Fibonacci Series
- C Check Palindrome or Not
- C Check Armstrong or Not
- C Find Armstrong Numbers
- C Find nCr and nPr
- C Find Profit Loss
- C Sum of their Square
- C First & Last Digit Sum
- C Sum of All Digit
- C Product of All Digit
- C Print Total Digit in Number
- C Check Perfect Number
- C Find Basic Gross Salary
- C Round Number to Integer
- C Print Series upto n Term
- C Find Factors of Number
- C if-else & Loop Programs
- C Check Even or Odd
- C Check Prime or Not
- C Check Alphabet or Not
- C Check Vowel or Not
- C Check Leap Year or Not
- C Is Reverse Equal Original
- C Make Calculator
- C Add Digits of Number
- Count Positive Negative Zero
- C Largest of Two Numbers
- C Largest of Three Numbers
- C Smallest of Two Numbers
- C Smallest of Three Numbers
- C Find Factorial of Number
- C Find LCM & HCF
- C Find LCM of n Numbers
- C Find HCF of n Numbers
- C Find Arithmetic Mean
- C Find Average, Percentage
- C Find Student Grade
- C Print Table of Number
- C Print Prime Numbers
- C Find Discount Purchase
- C Calculate Parcel Charge
- C Calculate Wage of Labor
- C Print Phone Bill
- C Conversion programs
- C Decimal to Binary
- C Decimal to Octal
- C Decimal to Hexadecimal
- C Binary to Decimal
- C Binary to Octal
- C Binary to Hexadecimal
- C Octal to Decimal
- C Octal to Binary
- C Octal to Hexadecimal
- C Hexadecimal to Decimal
- C Hexadecimal to Binary
- C Hexadecimal to Octal
- C Pattern Programs
- C Pattern Printing Programs
- C Print Diamond Pattern
- C Print Floyd's Triangle
- C Print Pascal's Triangle
- C Array Programs
- C 1D Array Programs
- C Linear Search
- C Binary Search
- C Largest Element in Array
- C Smallest Element in Array
- C Second Largest/Smallest
- C Count Even Odd
- C Array Element at Even
- C Array Element at Odd
- C Print Even Array Elements
- C Print Odd Array Elements
- C Sum/Product of Even/Odd
- C Reverse an Array
- C Insert Element in Array
- C Delete Element from Array
- C Merge Two Arrays
- C Bubble Sort
- C Selection Sort
- C Insertion Sort
- C Print Common Elements
- C 2D Array Programs
- C Add Two Matrices
- C Subtract Two Matrices
- C Transpose a Matrix
- C Multiply Two Matrices
- C Sum All Matrix Elements
- C Largest Element in Matrix
- C Print Row Column Total
- C 3D Array Programs
- C String Programs
- C Print String
- C Find Length of String
- C Compare Two String
- C Copy a String
- C Concatenate String
- C Reverse a String
- C Count Vowels Consonants
- C Replace Vowel in String
- C Delete Vowels from String
- C Delete Word from String
- C Frequency of Character
- C Count Word in String
- C Remove Spaces from String
- C Sort a String
- C Sort String in Alphabetical
- C Sort Words in Ascending
- C Sort Words in Descending
- C Uppercase to Lowercase
- C Lowercase to Uppercase
- C Swap Two Strings
- C Check Anagram or Not
- C Check Palindrome String
- C Print Number in Words
- C Print Successive Character
- C Character without Space
- C Remove Extra Spaces
- C File Programs
- C Read a File
- C Write Content to File
- C Read & Display File
- C Copy a File
- C Merge Two Files
- C Reverse File
- C Count All Character in File
- C List Files in Directory
- C Encrypt & Decrypt a File
- C Delete a File
- C Misc Programs
- Generate Random Numbers
- C Print Date Time
- C Print Message with Time
- C Get IP Address
- C Print Smiling face
- C Pass Array to Function
- Add Two Numbers using Pointer
- C Address of Variable
- C Shutdown Computer
- C Programming Tutorial
- C Tutorial
- C Programming Library
- C Standard Library
- C Programming Test
- C Programming Test
- Give Online Test
- All Test List
C Program to Swap Two Numbers
In this article, you will learn and get code on swapping of two numbers in C language using following approaches:
- using third Variable
- without using third Variable
- using Function and Pointer
What is Swapping of Two Numbers ?
Swapping of two numbers means, first number becomes second and second number becomes first. For example, if user enters any two number say 10 and 20. And let's suppose the two variables say num1 and num2 holds these two numbers. That is, num1=10 and num2=20. Then after swapping it will be like num1=20 and num2=10
Swap Two Numbers Using third Variable
Swapping of two numbers in C, becomes easy using third variable. That is, this program uses a variable named temp that helps a lot while performing the swap operation of given two numbers by user at run-time. Let's take a look at the program first
#include<stdio.h> #include<conio.h> int main() { int num1, num2, temp; printf("Enter Two Numbers:-\n"); printf("First Number: "); scanf("%d", &num1); printf("Second Number: "); scanf("%d", &num2); printf("\nBefore Swap:\n"); printf("First Number = %d\tSecond Number = %d", num1, num2); temp = num1; num1 = num2; num2 = temp; printf("\n\nAfter Swap:\n"); printf("First Number = %d\tSecond Number = %d", num1, num2); getch(); return 0; }
This program was build and run under Code::Blocks IDE. Here is its sample run:
Now enter the first number say 10 and then second number say 20. Press ENTER
key to see the following output:
The main block of code for swapping of two numbers is:
temp = num1; num1 = num2; num2 = temp;
For example, if user enters 10 as first number, then 10 gets initialized to num1. And if user enters 20 as second number, then 20 gets initialized to num2. That is, num1=10 and num2=20.
Now after executing the statement:
temp = num1;
The value of num1 (that is 10) gets initialized to temp. Therefore, temp=10. And after executing the statement:
num1 = num2;
The value of num2 (that is 20) gets initialized to num1. Therefore, num1=20. And again after executing the statement:
num2 = temp;
The value of temp (that is 10) gets initialized to num2. Therefore, num2=10. In this way, now the variable num1 holds the value that initially num2 has. Whereas the variable num2 holds the value that initially num1 has.
Note - Don't forgot to initialize the value of num1 to any third variable before initializing the value of num2 to it.
Swap Two Numbers Without using third Variable
Unlike the previous program, this program will not use any type of extra (third) variable in neither direct nor in-direct way:
#include<stdio.h> #include<conio.h> int main() { int num1, num2; printf("Enter Two Numbers:-\n"); printf("First Number: "); scanf("%d", &num1); printf("Second Number: "); scanf("%d", &num2); printf("\nBefore Swap:\n"); printf("First Number = %d\tSecond Number = %d", num1, num2); num1 = num1+num2; num2 = num1-num2; num1 = num1-num2; printf("\n\nAfter Swap:\n"); printf("First Number = %d\tSecond Number = %d", num1, num2); getch(); return 0; }
This program will produce the same output as of previous one. The following block of code is responsible for swapping of given two numbers. Here I've used the addition and subtraction operation:
num1 = num1+num2; num2 = num1-num2; num1 = num1-num2;
For example, let's suppose 10 and 20 are the two numbers entered by user. Therefore. num1=10 and num2=20. Now after executing the following statement:
num1 = num1+num2;
The value comes from num1+num2 (that will be 10+20) gets initialized to num1. Therefore, num1=30. Again after executing the following statement:
num2 = num1-num2;
The value comes from num1-num2 (that will be 30-20) gets initialized to num2. Therefore, num2=10. And again after executing the statement given below:
num1 = num1-num2;
The value comes from num1-num2 (that will be 30-10) gets initialized to num1. Therefore, num1=20. Now the value of first variable goes to second and the value of second variable goes to first one.
The Concept of Using + and - for Swapping
If there are two numbers. Suppose first number becomes total. Then if you subtract second number from total, you'll get the first number. Therefore it gets initialized to num2 (that now holds the initial value of num1). Again if you subtract the new value of second number (initial value of first number) from total, then you will get the initial value of second number. Therefore it gets initialized to num1 (that now holds the initial value of num2).
Swap Two Numbers Using Function and Pointer
This is the last program on swapping of two numbers. This program uses a user-defined function named swapFun() to swap the given two numbers by user:
#include<stdio.h> #include<conio.h> void swapFun(int *, int *); int main() { int num1, num2; printf("Enter Two Numbers:-\n"); printf("First Number: "); scanf("%d", &num1); printf("Second Number: "); scanf("%d", &num2); printf("\nBefore Swap:\n"); printf("First Number = %d\tSecond Number = %d", num1, num2); swapFun(&num1, &num2); printf("\n\nAfter Swap:\n"); printf("First Number = %d\tSecond Number = %d", num1, num2); getch(); return 0; } void swapFun(int *num1, int *num2) { int temp; temp = *num1; *num1 = *num2; *num2 = temp; }
This program also produces the same output as of previous two programs.
In above program, the & is called as address of operator. Whereas the * is called as value at operator. Therefore using the address of operator, we've passed the address of both the variables say num1 and num2 (that holds the two numbers entered by user) to the function named swapFun().
And inside the function swapFun(), we have used the value at operator to fetch the value available at the address of both the variables. The two variables gets swapped inside the function. Because we're using the address of both the variables, therefore the operation that has been done inside the function swapFun() effects the variable's value throughout the program. That is, when we print the value of two variables inside the main() function (after calling the function swapFun()), its value gets swapped.
To learn about Pointers or Functions in detail, then you can follow the separate tutorial on it.
Same Program in Other Languages
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