Converting Hexadecimal to Binary in C Without Using Arrays

Introduction

Hexadecimal to binary conversion is an essential skill for programmers who deal with low-level programming or network protocols. This article will guide you through the process of converting hexadecimal numbers to binary in C, without the need for arrays. We will explore the approach using bitwise operations and loops. If you are familiar with C programming, you will find this method straightforward and efficient.

The Approach

To convert a hexadecimal number to binary without arrays, we can leverage the power of bitwise operations, which manipulate individual bits of a number. Instead of using arrays to store binary digits, this method processes each hexadecimal digit directly as it is read from the input.

Step 1: Character Mapping to Binary Equivalents

The first step involves creating a mapping between each hexadecimal character and its binary representation. This can be implemented using a series of switch statements in a function named hexToBinary.

void hexToBinary(char hex) {
    switch (hex) {
        case '0': printf("0000"); break;
        case '1': printf("0001"); break;
        case '2': printf("0010"); break;
        case '3': printf("0011"); break;
        case '4': printf("0100"); break;
        case '5': printf("0101"); break;
        case '6': printf("0110"); break;
        case '7': printf("0111"); break;
        case '8': printf("1000"); break;
        case '9': printf("1001"); break;
        case 'A': case 'a': printf("1010"); break;
        case 'B': case 'b': printf("1011"); break;
        case 'C': case 'c': printf("1100"); break;
        case 'D': case 'd': printf("1101"); break;
        case 'E': case 'e': printf("1110"); break;
        case 'F': case 'f': printf("1111"); break;
        default: printf("0000"); break;
    }
}

This function receives a single character representing a hexadecimal digit and prints its corresponding 4-bit binary representation.

Step 2: Processing the Input

In the main function, we prompt the user to enter a hexadecimal number and read it as a string. We then iterate through each character in the string, converting them to binary using the hexToBinary function.

int main() {
    char hex[20]; // Input buffer for hexadecimal number
    printf("Enter a hexadecimal number: ");
    scanf("%s", hex);
    for (int i  0; hex[i] ! 0; i  ) {
        hexToBinary(hex[i]);
    }
    printf("
The binary representation is: ");
    return 0;
}

The main function reads the input, processes each hexadecimal digit, and prints the binary equivalent.

Example Execution

Let's see an example of how the provided code works:

Enter a hexadecimal number: 1A3F
The binary representation is: 0001101000111111

In this example, the hexadecimal number 1A3F is converted into its binary representation 0001101000111111.

Key Points

This implementation avoids the use of arrays for storing binary digits, making it more memory-efficient. The switch statement is a simple way to map each hexadecimal character to its binary equivalent. Proper input validation is crucial, especially when dealing with user input.

Note: Although this approach does not use arrays to store the binary digits, the input number is read as a string, which is technically an array. If the hex number is a constant or represented as a non-string input, the approach remains valid.

Conclusion

By using bitwise operations and loops, you can efficiently convert hexadecimal numbers to binary in C without relying on arrays. This method is particularly useful for low-level programming tasks. If you need to convert a constant hexadecimal value to a binary value, you can simply assign it directly:

int x  1256F;

This completes the hexadecimal to binary conversion in C without using arrays, providing a more memory-efficient approach.