<Codesignal> messageFromBinaryCode

Medium

You are taking part in an Escape Room challenge designed specifically for programmers. In your efforts to find a clue, you've found a binary code written on the wall behind a vase, and realized that it must be an encrypted message. After some thought, your first guess is that each consecutive 8 bits of the code stand for the character with the corresponding extended ASCII code.

Assuming that your hunch is correct, decode the message.

Example

For code = "010010000110010101101100011011000110111100100001", the output should be
messageFromBinaryCode(code) = "Hello!".

The first 8 characters of the code are 01001000, which is 72 in the binary numeral system. 72 stands for H in the ASCII-table, so the first letter is H.
Other letters can be obtained in the same manner.

Input/Output

• [execution time limit] 0.5 seconds (c)

• [input] string code

  A string, the encrypted message consisting of characters '0' and '1'.

  Guaranteed constraints:
  0 < code.length < 800.

• [output] string

  • The decrypted message.

// Prints help message to the console
// Returns a string
char * helloWorld(char * name) {
    char * answer = malloc(strlen(name) + 8);
    printf("This prints to the console when you Run Tests");
    strcpy(answer, "Hello, ");
    strcat(answer, name);
    return answer;
}

---

Solution

char *messageFromBinaryCode(char *code)
{
	char *decimalCode=(char *)calloc(strlen(code)/8+1,sizeof(char));

	for(int i=0;i<strlen(code);i+=8)
	{
		int N=0;

		for(int j=0;j<8;j++)
			N+=pow(2,7-j)*(code[i+j]=='1');
		decimalCode[i/8]=N;
	}

	return decimalCode;
}