Summary: In this tutorial, we will learn different ways to convert a decimal number into its corresponding binary representation in C programming language.
Example:
1 2 3 4 5 | Input: 1111 Output: 15 Input: 101 Output: 5 |
Method 1: Using While Loop
This is the standard way of converting a binary number to its corresponding decimal representation.
We multiply each binary digit with their corresponding exponential value of 2 (i.e. 2position_from_right -1) and sum them up.
In our program, we use a while loop to extract each binary digit, multiply them with 2x and sum them.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | #include <stdio.h> int main() { int bin, i=0, decimal = 0, digit; printf("Enter a Binary number: \n"); scanf("%d",&bin); while(bin != 0){ //extract the digit digit = bin%10; //multiply the digit with the 2x and add to the decimal decimal = decimal + pow(2,i) * digit; //remove the digit from the binary bin = bin/10; //increment the exponent power i = i+1; } printf("Decimal: %d", decimal); return 0; } |
Output:
Enter a Binary number:1011
Decimal: 11
Method 2: Using Recursion
We can also convert a binary number into a decimal using recursion.
In this method, we use the same approach as the above program but implement it in a recursive way.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | #include <stdio.h> //recursive function to convert binary to decimal int binToDec(int bin, int i){ /* *i represents the nth recursive call as well as *nth digit from right, so it can be used as an exponent */ //base condition if(bin == 0 || bin == 1) return pow(2,i)*bin; //extract binary digit, then multiply 2x and- //sum with the next recusive call int digit = bin%10; return (pow(2,i) * digit) + binToDec(bin/10, ++i); } int main() { int bin, decimal; printf("Enter a Binary number: \n"); scanf("%d",&bin); decimal = binToDec(bin,0); printf("Decimal: %d", decimal); return 0; } |
Output:
Enter a Binary number:101
Decimal: 5
In each recursive call, we extract a digit from the binary number and multiply it with its corresponding value of 2 raised to the power its position in the original binary number from the right.
Finally, we sum the multiplication result with the next recursive call result.
Note: Is it important to eliminate the last digit from binary on every recursive call.
In this programming example, we learned to convert a binary number into decimal in C. If you have any doubts or suggestions then please comment below.