Morse Code Translator

For an assignment, I'm unable to use the strings.
Only c-style strings.

From where did the C++ code you posted come? It seems
unlikely that you wrote all of it.

a5.cpp:59:27: error: excess elements in char array initializer

char morse_code[36]={".-","-...","-.-.","-..",".","..-.","--.",
"....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",
".-.","...","-","..-","...-",".--","-..-","-.-...

You have declared an array of chars, but the initializers
you specified are string literals. One alternative:

const char *morse_code[36] = { ".-","-...","-.-.","-..",  
".","..-.","--.","....","..",".---","-.-",".-..","--",  
"-.","---",".--.","--.-",".-.","...","-","..-","...-",  
".--","-..-","-.--","--..","-----",".----","..---",  
"...--","....-",".....","-....","--...","---..","----." };  

a5.cpp:82:10: error: invalid operands to binary expression
('char [255]' and 'int')

output += ' ';

The variable "output" is defined as an array of chars. So you
can't use the += operator as that only works with std::string.

You need to review how to build C-style strings (nul-terminated).

With suitable care when defining/declaring the char array which
is to hold the string being built - including presetting it to
binary zeros and ensuring that it is large enough - you can
make use of C runtime library functions such as:

strncat
https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/strncat-strncat-l-wcsncat-wcsncat-l-mbsncat-mbsncat-l?view=msvc-170

strcat
https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/strcat-wcscat-mbscat?f1url=%3FappId%3DDev15IDEF1%26l%3DEN-US%26k%3Dk(STRING%252Fstrcat);k(strcat);k(DevLang-C%252B%252B);k(TargetOS-Windows)%26rd%3Dtrue&view=msvc-170

strcpy
https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/strcpy-wcscpy-mbscpy?view=msvc-170

memcpy
https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/memcpy-wmemcpy?view=msvc-170

• Wayne

Note to the 2025 posters to this thread:

The thread and the OP's code are from year 2022.

I assume the OP has completed the assignment by now.

• Wayne

you don't define your morse code char break or word breaks. here is a simple sample with space as char break and / as word break (same as the sample javascript translator).

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>

char* morse_code[] = {
    ".-","-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..",
    "--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-",
    "-.--","--..","-----",".----","..---","...--","....-",".....","-....","--...",
    "---..","----.","/"
};
char alpha_num[] = {
    'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U',
    'V','W','X','Y','Z','0','1','2','3','4','5','6','7','8','9',' '
};

char* lookupMorse(char c) {
    for (int i=0; i < sizeof(alpha_num); ++i) {
        if (alpha_num[i] == c)
            return morse_code[i];
    }
    return "/";
}

char lookupAlpha(char* string) {
    for (int i=0; i < sizeof(alpha_num); ++i) {
        if (strcmp(morse_code[i], string) == 0)
            return alpha_num[i];
    }
    return ' ';
}

char* alphaToMorse(char* alpha) {
    char* morse = "";
    for (int i=0; i < strlen(alpha); ++i) {
        char* match = lookupMorse(alpha[i]);
        char* newMorse = malloc(strlen(morse) + strlen(match) + 1);
        strcpy(newMorse,morse);
        strcat(newMorse,match);
        strcat(newMorse," ");
        morse = newMorse;
    }
    return morse;
}

char* morseToAlpha(char* morse) {
    bool done = false;
    int morseCharCount = 0;
    
    for (char* p = morse; !done; ++p) {
        if (*p == ' ' || (done = *p == 0)) ++morseCharCount;
    }
    
    char* alpha = malloc(++morseCharCount);
    char* pa = alpha;
    char morseBuff[8];
    char* endOfBuff = &morseBuff[7];
    char* pb = morseBuff;
    
    for (char* pm = morse, done = false; !done; ++pm) {
        char m = *pm;
        if (m == ' ' || (done = m == 0)) {
            *pb = 0;
            pb = morseBuff;
            *pa++ = lookupAlpha(morseBuff);
        } else {
            if (pb < endOfBuff)
                *pb++ = m;
            else
                *pb = 0;
        }
    }
    *pa = 0;

    return alpha;
}

int main(int argc, const char* argv[]) {
    printf("%s\n",alphaToMorse("HELLO WORLD"));
    printf("%s\n",morseToAlpha("--. --- --- -.. / -... -.-- . ---------"));
    return 0;
}