Arrays not outputting correctly - C++

Question

I am writing a C++ console application and I'm turning a into 1, b into 2 and so on. Thing is, it's outputting numbers like 48 and 52 - even though the array I'm basing it off only goes up to 26.

Here's the code:

void calculateOutput() {

    while (input[checkedNum] != alphabet[checkedAlpha]) {
        checkedAlpha++;
        if (checkedAlpha > 27) {
            checkedAlpha = 0;
        }
    }

    if (input[checkedNum] == alphabet[checkedAlpha]) {
        cout << numbers[checkedAlpha] << "-";
        checkedAlpha = 0;
        checkedNum++;
        calculateOutput();
    }
}

Here is my number and alphabet arrays:

char alphabet [27] = { 'a','b','c','d','e','f','g','h','i','j','k','l','m','o','p','q','r','s','t','u','v','w','x','y','z',' '};

int numbers [27] = { '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','0' };

Where does the numbers array come from? Regardless, your output (stuff like 48 and so on) sounds like ASCII values. — nondestructive
– nondestructive, Commented Aug 22, 2017 at 5:40
@plezhelpmeh please edit the question with the added data... — MordechayS
– MordechayS, Commented Aug 22, 2017 at 5:42

kocica · Accepted Answer · 2017-08-22 05:56:46Z

3

Its int array so it means that it will save ASCII values of characters.

If you would look carefully on ASCII table, you would find out that 48,49,50,... are ascii values of numbers 0,1,2,...

What you have to do is deduct value of first number in table -> '0' (48)

cout << numbers[checkedAlpha] - '0' << "-";

or better, save numbers as numbers not characters

 int numbers [27] = { 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18',19,20,21,22,23,24,25,26,0 };

Btw. here is hint which make it easier for you

tolower(inputAlphabet[index]) - 'a' + 1  // For 'a' output is 1 and so on :-)

edited Aug 22, 2017 at 5:56

answered Aug 22, 2017 at 5:42

kocica

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1 Comment

kocica Over a year ago

I'm glad it helped you, remember that ascii table. :-)

Michaël Roy · Accepted Answer · 2017-08-22 05:47:14Z

0

The algorithm to get the number (i9ndex) of the letters of the alphabet is quite simple. No need for tables, a simple subtraction does the trick.

int getLetterIndex(char c)
{
    // returns -1 if c is not a letter
    if ('a' <= c && c <= 'z')
        return 1 + c - 'a';
    if ('A' <= c && c <= 'Z')
        return 1 + c - 'A';
    return -1; 
}

answered Aug 22, 2017 at 5:47

Michaël Roy

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