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a single charcter displaying in lcd using pointer

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thannara123

thannara123

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hello experts ,
I want to display "*" in the following codes - for memory reduction please help me
Code: 
switch (keyCode) //generating key characeter to display on LCD
        {
            case (11):
            string("1");    [COLOR=#ff0000] // want change  string(*g);    *g contain star "*"[/COLOR]
            dis_cmd(k++);
            key[x]=1;
            x++;
            pos++;
            break;
            
            
            case (10):
            //dis_cmd(k++);
            string("2");        [COLOR=#ff0000]// want change  string(*g);    *g contain star "*"    [/COLOR]
            dis_cmd(k++);
            key[x]=2;
            x++;
            pos++;
            break;
            
            case (9):
            string("3");
            dis_cmd(k++);
            key[x]=3;
            x++;
            pos++;
            break;
            
            case (8):
            string("4"); [COLOR=#ff0000]// want change  string(*g);    *g contain star "*"[/COLOR]
            dis_cmd(k++);
            key[x]=4;
            x++;
            pos++;
            break;
            
            case (7):
            //dis_cmd(k++);
            string("5");     [COLOR=#ff0000]// want change  string(*g);    *g contain star "*"[/COLOR]
            dis_cmd(k++);
            key[x]=5;
            x++;
            pos++;
            break;
            
            case (6):
            string("6");   [COLOR=#ff0000]// want change  string(*g);    *g contain star "*"[/COLOR]
            dis_cmd(k++);
            key[x]=6;
            x++;
            pos++;
            break;
            
            case (5):
            string("7");    [COLOR=#ff0000]// want change  string(*g);    *g contain star "*"[/COLOR]
            dis_cmd(k++);
            key[x]=7;
            x++;
            pos++;
            break;
            
            case (4):
            string("8");
            dis_cmd(k++);
            key[x]=8;
            x++;
            pos++;
            break;
            
            case (3):
            string("9");
            dis_cmd(k++);
            key[x]=9;
            x++;
            pos++;
            break;
            
            case (2):
            //string("*");
            //dis_cmd(k++);
            //key[x]=0;
            //x++;
            //pos++;
            break;

            case (1):
            string("0");
            dis_cmd(k++);
            key[x]=0;
            x++;
            pos++;
            break;

            //case (12):
            //break;
            
            //default: ;
            //loop: ;
        }

        _delay_loop_2(300);

here the string function writes only star "*" . then how to change it
please help me.
thanks
 

Hello!

Some ideas:
- You don't say what the variable x is. You don't specify pos either, but I can more
or less that it's a position somewhere, possibly on the screen
- You don't need the "key" array, because for any value, key[x] = keycode.

So basically (just guessing), you get a key code and you want to display another value.
For 12, display nothing and return, for 11, display 1, for 10, display 2, etc...
Why not writing:

Code C - [expand]
1
2
3
4
5
6
7
8
9
10
11
12
13

char str[2];  // This should not be placed in your loop as it does not change
str[1] = 0;  // This should not be placed in your loop as it does not change
 
if((key code < 12) && (ketycode > 2)) {
    str[0] = '0' + 12 - keycode;
    string(str);
    pos++;
}
else if(keycode == 1) {
   str[0] = '0';
    string(str);
    pos++;
}


And you ignore cases 2 (which is commented out) and 12. The str array has 2 characters
because a C string is supposed to be 0 terminated. Now you may also consider a simpler
way than a string, a kind of put char(c) which would write a single char to the screen.
Then if g is a string, you function would write pitcher(*g).

Now for your question, you cannot directly change to something like *g. Your function called string
expects a string, which is usually a pointer to char. You can use string(*g) only if g is a char**.
Then *g would be a char * (and **g a char).
Just a question: if you tell me I want a function that displays one character, I would understand.
Now what is the purpose of changing to string(*g);? Just for the beauty of string(*g);? What is
the final purpose of this change?

Now as a general advice, (please don't think this is rude): think first, or in other words, don't
program first. Look at what you have to do (in this case displaying the value 12 - keycode for
most of the codes, and then put it into code.
The code you wrote is long, subject to bugs. I'm not pretending I am an expert, but at least
the code I wrote and which should do roughly the same thing as yours is about 1/10 the size of
yours.
Besides this, I have another personal "rule", I know that some may not agree, but here it is:
NEVER write a function that takes more than one screen to display. You should be able to see
any function you write in a single page. On a modern screen, this allows you about 50 lines,
which is a lot.
If your function is about to take more than one screen, then split it.

Dora.
 
See the dis_cmd() function> In that you are passing *msg++. You are passing strings instead of *msg++. Whether you use some string like str[] or *str the function which calls should pass a string value like string("1"). If you use *g where will be the strings "1", "2", etc... Yo again have to pass strings like "1", "2", etc... to the function.
 
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