- C++ Programming Examples
- C++ Programming Examples
- C++: Hello World
- C++: Get Input
- C++: Print Integer
- C++: Add two numbers
- C++: Add, Sub, Multiply, Div
- C++: Add Digits
- C++: Find Average and Percentage
- C++: Find Arithmetic Mean
- C++: Sum of n Natural Numbers
- C++: Sum of n Numbers
- C++: Square's Area and Perimeter
- C++: Rectangle's Area and Perimeter
- C++: Triangle's Area and Perimeter
- C++: Area and Circumference
- C++: Find Simple Interest
- C++: Fahrenheit to Celsius
- C++: Celsius to Fahrenheit
- C++: Print Prime Numbers
- C++: Reverse a Number
- C++: Swap Two Numbers
- C++: Print Multiplication Table
- C++: Find Factorial of a Number
- C++: Find Factors of a Number
- C++: Find HCF and LCM
- C++: Create a Calculator
- C++: Count Digits in a Number
- C++: First and Last Digit Sum
- C++: Product of Number Digits
- C++: Sum of Squares of Digits
- C++: Interchange Digits of Number
- C++ if-else 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++: Check Reverse equals Original
- C++: Check Perfect Number
- C++: Check Palindrome or Not
- C++: Check Armstrong or Not
- C++: Divisibility Test
- C++: Find Labor Wage
- C++: Find Discounted Price
- C++: Find Shipping Charge
- C++: Find Telephone Bills
- C++: Calculate Student Grade
- C++: Largest of Two Numbers
- C++: Largest of Three Numbers
- C++ Number Conversion
- 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 Programs
- C++: Print Diamond Pattern
- C++: Print Floyd's Triangle
- C++: Print Pascal's Triangle
- C++ Array Programs
- C++: 1D Array Program
- C++: Linear Search
- C++: Binary Search
- C++: Largest Element in an Array
- C++: Smallest Element in an Array
- C++: Find Second Largest Element
- C++: Find Second Smallest Element
- C++: Sum of All Elements
- C++: Multiply All Elements
- C++: Element in Even Position
- C++: Element in Odd Position
- C++: Print Even Numbers in Array
- C++: Print Odd Numbers in Array
- C++: Count Even or Odd Numbers
- C++: Sum of Even or Odd Numbers
- C++: Count Positive, Negative, Zero
- C++: Reverse an Array
- C++: Insert an Element
- C++: Delete an Element
- C++: Merge two Arrays
- C++: Bubble Sort
- C++: Selection Sort
- C++: Insertion Sort
- C++: Common Elements
- C++: 2D Array Programs
- C++: Add Two Matrices
- C++: Subtract Two Matrices
- C++: Transpose Matrix
- C++: Multiply Two Matrices
- C++: 3D Array Programs
- C++ String Programs
- C++: Print String
- C++: Find String Length
- C++: Compare Two Strings
- C++: Copy String
- C++: String Concatenation
- C++: Reverse a String
- C++: Delete Vowels from a String
- C++: Delete a Word from a String
- C++: Count Characters in a String
- C++: Count Words in a String
- C++: Frequency of Words
- C++: Remove Spaces from Strings
- C++: Sort a String
- C++: Uppercase to Lowercase
- C++: Lowercase to Uppercase
- C++: Swap Two Strings
- C++: Check the Anagram or Not
- C++: Capitalize All Words in a String
- C++: Get Numbers from a String
- C++ File Programs
- C++: Read a File
- C++: Write Content to a File
- C++: Append Data to a File
- C++: Read and Display File
- C++: Copy a File
- C++: Merge Two Files
- Count Characters in a File
- C++: Capitalize Every Word
- C++: List Files in Directory
- C++: Delete a File
- C++: Encrypt and Decrypt a File
- C++ Misc Programs
- C++: Print ASCII Value
- C++: Add Binary Numbers
- C++: Generate Random Numbers
- C++: Print a Smiling Face
- C++: Days into Years and Months
- C++: Add Two Numbers using Pointer
- C++: Print Fibonacci Series
- C++: Generate Armstrong Numbers
- C++: Find nCr and nPr
- C++: Get IP Address
- C++: Print Date and Time
- C++: Shutdown and Restart Computer
- C++ Programming Tutorial
- C++ Tutorial
C++ Program to Interchange the Digits of a Number
In this article, you will learn and get code to interchange the digits of a number entered by the user at run-time in C++. Here is the list of programs available in this article:
- Interchange the first and last digit of a number
- Interchange the first and last digit of a number using an array
- Interchange any two digits of a number
Interchange the first and last digit of a number in C++
To interchange the first and last digits of a number in C++ programming, you have to ask the user to enter the number. And then interchange its first and last digit as shown in the program given below:
The question is: write a program in C++ to interchange the first and last digits of a number. Here is its answer:
#include<iostream> using namespace std; int main() { int num, rem, temp, rev=0, noOfDigit=0; int noOfDigitTemp, revNum, remTemp; cout<<"Enter the Number: "; cin>>num; temp = num; while(temp>0) { temp = temp/10; noOfDigit++; } if(noOfDigit<2) { cout<<"\nIt is a Single-digit Number!"; cout<<"\nTry again with a Number with Two or More Digits!"; } else if(noOfDigit==2) { temp = num; while(temp>0) { rem = temp%10; rev = (rev*10)+rem; temp = temp/10; } cout<<"\nFirst and Last Digit Interchanged Successfully!"; cout<<"\n\nNew Number = "<<rev; } else { temp = num; while(temp>0) { rem = temp%10; rev = (rev*10)+rem; temp = temp/10; } revNum = rev; rev = 0; temp = num; noOfDigitTemp = noOfDigit; while(temp>0) { remTemp = revNum%10; if(noOfDigitTemp==noOfDigit) { rem = temp%10; rev = (rev*10)+rem; } else if(noOfDigitTemp==1) { rem = temp%10; rev = (rev*10)+rem; } else { rev = (rev*10)+remTemp; } temp = temp/10; revNum = revNum/10; noOfDigitTemp--; } cout<<"\nFirst and Last Digit Interchanged Successfully!"; cout<<"\n\nNew Number = "<<rev; } cout<<endl; return 0; }
This program was built and runs under the Code::Blocks IDE. Here is its sample run:
Now supply any number, say 1234, and press ENTER to interchange the first (1) and last (4) digits of this number. After exchanging the first and last digits, print the new number as shown in the snapshot of the sample run given below:
Here is another sample run with user input 12, a two-digit number:
Here is one more sample run with user input 3, a single-digit number:
What happens if the user enters a number that ends in 0? Or if the user enters a number that has 0 as its last digit, then the above program produces the following output in this case:
To solve this problem, we have another program for you. This program does the same job, but using an array. Let's have a look at the program given below.
In C++, use an array to swap the first and last digits
This program does the same job, which is to interpolate the first and last digits of a number given by the user using an array.
#include<iostream> using namespace std; int main() { int num, rem, temp, rev=0, noOfDigit=0, arr[10], i; cout<<"Enter the Number: "; cin>>num; temp = num; while(temp>0) { temp = temp/10; noOfDigit++; } temp = num; while(temp>0) { rem = temp%10; rev = (rev*10)+rem; temp = temp/10; } for(i=0; i<noOfDigit; i++) { rem = rev%10; arr[i] = rem; rev = rev/10; } if(noOfDigit==1) { cout<<"\nIt is a Single-digit Number!"; cout<<"\nTry again with a Number with Two or More Digits!"; } else if(noOfDigit==2) { temp = arr[0]; arr[0] = arr[1]; arr[1] = temp; cout<<"\nFirst and Last Digit Interchanged Successfully!"; cout<<"\n\nNew Number = "<<arr[0]<<arr[1]; } else { i=0; temp = arr[i]; arr[i] = arr[noOfDigit-1]; arr[noOfDigit-1] = temp; cout<<"\nFirst and Last Digit Interchanged Successfully!"; cout<<"\n\nNew Number = "; for(i=0; i<noOfDigit; i++) cout<<arr[i]; } cout<<endl; return 0; }
Here is its sample run with user input, 1230:
Interchange any two digits of a number in C++
This program is created to interchange any two digits of a number. Any two-digit number allows you to swap the digit at position 2 with the digit at position 5, say:
For example, if a user enters the number 23706 and wishes to swap the digit in the second position (3) with the digit in the fifth position (6), then the new number, after changing the required digit, will be 26703.
#include<iostream> using namespace std; int main() { int num, posFirst, posSecond; int rem, temp, rev=0, noOfDigit=0, arr[10], i; cout<<"Enter the Number: "; cin>>num; temp = num; while(temp>0) { temp = temp/10; noOfDigit++; } if(noOfDigit==1) { cout<<"\nIt is a Single-digit Number!"; cout<<"\nTry again with a Number with Two or More Digits!"; } else { cout<<"\nInterchange the Digit at Position: "; cin>>posFirst; cout<<"With Digit at Position: "; cin>>posSecond; } if(posFirst>noOfDigit || posSecond>noOfDigit) cout<<"\nInvalid Position!"; else { temp = num; while(temp>0) { rem = temp%10; rev = (rev*10)+rem; temp = temp/10; } for(i=0; i<noOfDigit; i++) { rem = rev%10; arr[i] = rem; rev = rev/10; } i=0; temp = arr[posFirst-1]; arr[posFirst-1] = arr[posSecond-1]; arr[posSecond-1] = temp; cout<<"\nDigits Interchanged Successfully!"; cout<<"\n\nNew Number = "; for(i=0; i<noOfDigit; i++) cout<<arr[i]; } cout<<endl; return 0; }
Here is its sample run with user input, 123403 as a number, and 3 and 5 as digit positions to interchange:
The same program in different languages
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