- 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 Convert Decimal to Binary
In this article, you will learn about and get C++ code for decimal to binary conversion. The program is created using the following approaches:
- Decimal to Binary using an Array
- Decimal to Binary without using an array
- Decimal to Binary using a user-defined function
Some extra programs are also available. However, before going through all of the programs available here, if you are unfamiliar with the steps used for the conversion, you can refer to Decimal to Binary to get everything you need.
Decimal to Binary using an Array in C++
To convert a decimal number to a binary number in C++ programming, you have to ask the user to enter the decimal number first. and then convert it into its equivalent binary value. Print its equivalent binary value on the output as shown in the program given below.
The question is: write a program in C++ to receive a decimal number and print its equivalent value in binary. The answer to this question is given below:
#include<iostream> using namespace std; int main() { int decimalNum, binaryNum[20], i=0; cout<<"Enter the Decimal Number: "; cin>>decimalNum; while(decimalNum!=0) { binaryNum[i] = decimalNum%2; i++; decimalNum = decimalNum/2; } cout<<"\nEquivalent Binary Value: "; for(i=(i-1); i>=0; i--) cout<<binaryNum[i]; cout<<endl; return 0; }
This program was built and runs under the Code::Blocks IDE. Below is a sample run:
Now supply any decimal number input, say 105, and press the ENTER key to print its equivalent value in the binary number system as shown in the output given below:
The dry run of the above program with user input 105 (a decimal number) goes like this:
- Initial value, i=0
- When the user enters a decimal number, say 105, then it gets stored in decimalNum. So decimalNum=105
- The while loop's condition decimalNum!=0 is now evaluated.
- The condition decimalNum!=0 or 105!=0 is evaluated to be true, therefore program flow goes inside the loop.
- And decimalNum%2 or 105%2 or 1 gets initialized to binaryNum[i] or binaryNum[0]. So, binaryNum[0]=1
- The value of i gets incremented. Now i=1
- And decimalNum/2 or 52 is set to decimalNum. Now decimalNum=52
- Program flow goes back and evaluates the condition of the while loop again with a new value of 52.
- Because the condition again evaluates to being true, the program flow again goes inside the loop.
- And again, decimalNum%2 or 52%2 or 0 gets initialized to binaryNum[i] or binaryNum[1]. So binaryNum[1]=0
- Again the value of i gets incremented. So i=2
- After that, decimalNum/2, 52/2, or 26 is initialized to decimalNum. So decimalNum=26
- Process the same, from step no. 8 to 12 with the new value of decimalNum and i.
- On continuing the process in a similar way until the condition of the while loop evaluates to be false,
we will get the values of binaryNum[] as:
- binaryNum[0]=1
- binaryNum[1]=0
- binaryNum[2]=0
- binaryNum[3]=1
- binaryNum[4]=0
- binaryNum[5]=1
- binaryNum[6]=1
- When the value of decimalNum becomes equal to 0, then the condition decimalNum!=0 or 0!=0 evaluates to be false, and therefore the evaluation of the while loop gets ended. The value of binaryNum[] is then printed using the for loop.
- The value of binaryNum[] is printed from the last to the 0th index.
- That will be 1101001
From 1 to 20, convert decimal to binary
Here is another program that converts all the decimal numbers from 1 to 20 to their equivalent binary values.
#include<iostream> using namespace std; int main() { int decimalNum, binaryNum[10], i, k; cout<<" Decimal Number\t\tBinary Number\n"; for(k=1; k<=20; k++) { i=0; decimalNum = k; while(decimalNum!=0) { binaryNum[i] = decimalNum%2; i++; decimalNum = decimalNum/2; } cout<<" "<<k<<"\t\t\t"; for(i=(i-1); i>=0; i--) cout<<binaryNum[i]; cout<<endl; } cout<<endl; return 0; }
Here is the output produced by the above program:
Decimal to Binary Conversion without Array
The question is: write a program in C++ that converts a decimal number to a binary number without using an array. Here is its answer. This program doesn't use an array to convert any given number in decimal to its equivalent binary value.
#include<iostream> using namespace std; int main() { int decimalNum, binaryNum=0, mul=1, rem; cout<<"Enter the Decimal Number: "; cin>>decimalNum; while(decimalNum>0) { rem = decimalNum%2; binaryNum = binaryNum+(rem*mul); mul = mul*10; decimalNum = decimalNum/2; } cout<<"\nEquivalent Binary Value: "<<binaryNum; cout<<endl; return 0; }
Here is a sample run with 18 as a decimal number as user input:
Decimal to binary conversion in C++, using a user-defined function
This program also does the same job as the previous program. The only difference is that this program was created using a user-defined function, DecimalToBinary(). That is, this function was created to convert decimal to binary.
This function takes a decimal number as its argument and returns its equivalent binary value. The return value is initialized to binaryNum (in the main() function). Print the value of "binaryNum" as output.
#include<iostream> using namespace std; int DecimalToBinary(int); int main() { int decimalNum, binaryNum; cout<<"Enter the Decimal Number: "; cin>>decimalNum; binaryNum = DecimalToBinary(decimalNum); cout<<"\nEquivalent Binary Value: "<<binaryNum; cout<<endl; return 0; } int DecimalToBinary(int decimalNum) { int binaryNum=0, mul=1, rem; while(decimalNum>0) { rem = decimalNum%2; binaryNum = binaryNum+(rem*mul); mul = mul*10; decimalNum = decimalNum/2; } return binaryNum; }
It will produce the same output as the previous program. You can also use user-defined functions to create the same purpose program:
#include<iostream> using namespace std; int DecimalToBinary(int, int); int binaryNum[20]; int main() { int decimalNum, i; cout<<"Enter the Decimal Number: "; cin>>decimalNum; i = DecimalToBinary(decimalNum, 0); cout<<"\nEquivalent Binary Value: "; for(i=(i-1); i>=0; i--) cout<<binaryNum[i]; cout<<endl; return 0; } int DecimalToBinary(int decimalNum, int i) { while(decimalNum!=0) { binaryNum[i] = decimalNum%2; i++; decimalNum = decimalNum/2; } return i; }
The same program in different languages
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