Confusion with Uppercase, digit and integer "zero" output in the code-CodePudding

I am trying to write a code in C , that does the following:

If the user inputs A, the program outputs ALPHA
If the user inputs B, the program outputs BRAVO

And so on with all the Nato Alphabet

Also the code must:

If user inputs 0, program outputs Zero
If user inputs something that is not uppercase letter or digit, the program outputs shou Not Recognized

Here is the whole code that I have created to complete these tasks.

# include <iostream>

using namespace std;

int main () {

    // Declare the characters in respect to the alphabet

    char A[] = "Alfa"; char B[] = "Bravo"; char C[] = "Charlie"; char D[] = "Delta"; char E[] = "Echo";
    char F[] = "Foxtrot"; char G[] = "Golf"; char H[] = "Hotel"; char I[] = "India"; char J[] = "Juliet"; char K[] = "Kilo";
    char L[] = "Lima"; char M[] = "Mike"; char N[] = "November"; char O[] = "Oscar"; char P[] = "Papa";
    char Q[] = "Quebec"; char R[] = "Romeo"; char S[] = "Sierra"; char T[] = "Tango"; char U[] = "Uniform";
    char V[] = "Victor"; char W[] = "Whiskey"; char X[] = "Xray"; char Y[] = "Yankee"; char Z[] = "Zulu";

    // Declare the possible characters

    string chosenCharacter;

    // Create the terminal input message 

    cout << "Please insert a letter: "<< endl;

    cin >> chosenCharacter;

    // Declare the scenarios for output [letter = word]

    if (chosenCharacter == A) {
    
        cout << "Your received message is: " << A << endl;

    }

    else if (chosenCharacter == B)
    {
        cout << "Your received message is: " << B << endl;
    }

    else if (chosenCharacter == C)
    {
        cout << "Your received message is: " << D << endl;
    }
    
    else if (chosenCharacter == E)
    {
        cout << "Your received message is: " << E << endl;
    }

    else if (chosenCharacter == F)
    {
        cout << "Your received message is: " << F << endl;
    }

    else if (chosenCharacter == G)
    {
        cout << "Your received message is: " << G << endl;
    }

    else if (chosenCharacter == H)
    {
        cout << "Your received message is: " << H << endl;
    }

    else if (chosenCharacter == I)
    {
        cout << "Your received message is: " << I << endl;
    }

    else if (chosenCharacter == J)
    {
        cout << "Your received message is: " << J << endl;
    }

    else if (chosenCharacter == K)
    {
        cout << "Your received message is: " << K << endl;
    }

    else if (chosenCharacter == L)
    {
        cout << "Your received message is: " << L << endl;
    }

    else if (chosenCharacter == M)
    {
        cout << "Your received message is: " << M << endl;
    }

    else if (chosenCharacter == N)
    {
        cout << "Your received message is: " << N << endl;
    }

    else if (chosenCharacter == O)
    {
        cout << "Your received message is: " << O << endl;
    }

    else if (chosenCharacter == P)
    {
        cout << "Your received message is: " << P << endl;
    }

    else if (chosenCharacter == Q)
    {
        cout << "Your received message is: " << Q << endl;
    }

    else if (chosenCharacter == R)
    {
        cout << "Your received message is: " << R << endl;
    }

    else if (chosenCharacter == S)
    {
        cout << "Your received message is: " << S << endl;
    }

    else if (chosenCharacter == T)
    {
        cout << "Your received message is: " << T << endl;
    }

    else if (chosenCharacter == U)
    {
        cout << "Your received message is: " << U << endl;
    }

    else if (chosenCharacter == V)
    {
        cout << "Your received message is: " << V << endl;
    }

    else if (chosenCharacter == W)
    {
        cout << "Your received message is: " << W << endl;
    }

    else if (chosenCharacter == X)
    {
        cout << "Your received message is: " << X << endl;
    }

    else if (chosenCharacter == Y)

    {
        cout << "Your received message is: " << Y << endl;
    }

    else if (chosenCharacter == Z)

    {
    
        cout << "Your received message is: " << Z << endl;

    }
    
    // Check if the input is not a upper Case letter

    else if (chosenCharacter =! isupper) {

        cout << "Not Recognized" << endl;
    }

    // Check if the input is not a digit

    else if (chosenCharacter =! isdigit) {

        cout << "Not Recognized" << endl;

    }

    // Check if the input is zero

    else if (chosenCharacter == 0) {

        cout << "Zero" << endl;

    }
    
}

Unfortunately I am struggling to check if the inputed information is not upperCase,digit or Zero as that part of the code seems to not be working as intended, as I am recieving the following error messeages.

// Check if the input is not upper Case letter

cannot resolve overloaded function 'isupper' based on conversion to type 'bool'

// Check if the input is not a digit

cannot resolve overloaded function 'isdigit' based on conversion to type 'bool'

//Check if the input is zero

no match for 'operator==' (operand types are 'std::string' {aka 'std::__cxx11::basic_string'} and 'int')

I am stuck with this issue and would appreciate some help. Could you please provide some improvements for the code, so that all of the 3 functions would be working as inteded?

CodePudding user response：

There are several issues identified in your code in the comments. Notably your code of C-style strings and a std::string to represent a single character.

The most straightforward way to solve this problem is going to be to use. std::map to map a char to a std::string. A simple example:

#include <map>
#include <string>
#include <iostream>

int main() {
  std::map<char, std::string> abc = {
    {'A', "Alfa"},   {'B', "Bravo"},    {'C', "Charlie"},
    {'D', "Delta"},  {'E', "Echo"},     {'F', "Foxtrot"},
    {'G', "Golf"},   {'H', "Hotel"},    {'I', "India"},
    {'J', "Juliet"}, {'K', "Kilo"},     {'L', "Lima"},
    {'M', "Mike"},   {'N', "November"}, {'O', "Oscar"},
    {'P', "Papa"},   {'Q', "Quebec"},   {'R', "Romeo"},
    {'S', "Sierra"}, {'T', "Tango"},    {'U', "Uniform"},
    {'V', "Victor"}, {'W', "Whiskey"},  {'X', "Xray"},
    {'Y', "Yankee"}, {'Z', "Zulu"},     {'0', "Zero"}
  };

  char ch;
  std::cin >> ch;

  auto code = abc.find(ch);

  if (code == abc.end())
    std::cout << "Not recognized." << std::endl; 
  else
    std::cout << code->second << std::endl;

  return 0;
}

CodePudding user response：

This can be simplified if we can assume ASCII character set and that 'Z' - 'A' is a positive number.

char const * text[] =
{
    "Alfa",    "Bravo",  "Charlie", "Delta",    "Echo",
    "Foxtrot", "Golf",   "Hotel",   "India",    "Juliet",
    "Kilo",    "Lima",   "Mike",    "November", "Oscar",
    "Papa",    "Quebec", "Romeo",   "Sierra",   "Tango",
    "Uniform", "Victor", "Whiskey", "Xray",     "Yankee",
    "Zulu",
};

//...
cin >> selection_letter;
selection_letter = std::toupper(selection_letter);
if (isalpha(selection_letter))
{
    const unsigned index = selection_letter - 'A';
    std::cout << selection_letter << ": " << text[index] << "\n";
}
//...

The zero check and numerics can be handled in another table.