Cannot pass char parameter to a function.

[Francesco cembrola]

The code below works OK.
It calles the function 'text_pos' an passes ascii caracters to it.
Then 'text_pos' convert them to ascii codes.
These are send to the I2C interface to controll an LCD display.
These characters represent the cursor coordinates on the LCD display

However I need to modify the code to pass parameters like : text_pos ('34',65'), (two digits).
otherwise I can only get the coordinates up to 9X,9Y.

If I call the function like: text_pos('10','12'), how do I read each of the digit indivually?

I need to assign something like: int X0= first digit of row. int X1= second digit of row.
int Y0=first digit of col. int Y1 = second digit of col.

Do i need to declare two arrayes in the function?
I have tried some experiments with out success.

Can you please help to modify the code?

Thank you.:-?

#include <p18F26k22.h>
#include <stdlib.h>
#include <delays.h>
#include <stdio.h>
#include <I2C.h>
#include <string.h>

void text_pos(char row, char col);

int xpos=0;
int ypos=0;

void main(void)
{ 

text_pos('5','9');  // call function to set cursor coordinates

}


void text_pos(char row,char col)

}  
xpos=col;// convert char to int
// xpos second digit

ypos=row; 
// ypos second digit
 
StartI2C2();  
putcI2C2(0x64);   //device address
putcI2C2(27);     //esc
putcI2C2(91);     // [ 
putcI2C2(ypos);   //row

// putcI2C2(ypos);// need here the second digit for y pos

putcI2C2(59);     // ;
putcI2C2(xpos);   // column
// putcI2C2(xpos2); //need here the second digit for X pos

putcI2C2(72);      // H 
Delay10KTCYx(100);   
StopI2C2();
     
 }

 

[alexan_e]

You can only pass an array pointer to the function (this is C right?)

char my_array[]="123456";

void my_function(char *array_p)
{
char a,b,c;

  a=array_p[0];    // this is the first char of the array
  b=array_p[1];    // this is the second char of the array
  c=array_p[2];    // this is the third char of the array
}

Call it using

my_function(my_array);

If you want you can use two or more pointer parameters

 

[Francesco cembrola]

You can only pass an array pointer to the function (this is C right?)

char my_array[]="123456";

void my_function(char *array_p)
{
char a,b,c;

  a=array_p[0];    // this is the first char of the array
  b=array_p[1];    // this is the second char of the array
  c=array_p[2];    // this is the third char of the array
}

Call it using

my_function(my_array);

If you want you can use two or more pointer parameters

Hi thank you for the speedy replay.
I think you have over estimated my knoledge of C.

I do understand the first part of your code.

But I still don get it how to read those digits once they have been passed to the function.

Regards

Francesco

 

[alexan_e]

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Code C - [expand]
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char my_array[]="123456";   // I declare an array
 
void my_function(char *array_p)  // declaring a function that takes a char pointer as a parameter
{
char a,b,c;  // declare local char variables a,b,c
 
  a=array_p[0];    // assign to a the first character of the array (in this example '1')
  b=array_p[1];    // assign to a the second character of the array  (in this example '2')
  c=array_p[2];    // assign to a the third character of the array  (in this example '3')
}
 
my_function(my_array);  // call the function using the address of the first character of the array, my_array is the same as &my_array[0]

---

 

[Francesco cembrola]

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Code C - [expand]
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char my_array[]="123456";   // I declare an array
 
void my_function(char *array_p)  // declaring a function that takes a char pointer as a parameter
{
char a,b,c;  // declare local char variables a,b,c
 
  a=array_p[0];    // assign to a the first character of the array (in this example '1')
  b=array_p[1];    // assign to a the second character of the array  (in this example '2')
  c=array_p[2];    // assign to a the third character of the array  (in this example '3')
}
 
my_function(my_array);  // call the function using the address of the first character of the array, my_array is the same as &my_array[0]

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Hi alex,

thanks agoin for the replay.
I will be modifying may code tomorrow following your example. I will post my outcome.

regards

francesco