Passing strings to function?

[armondo522]

Hope someone cane help me out here. I am writting a program that will pass variable strings to a 4 line I2C LCD display. I would like to have 4 separate routines , one for each line and just pass the string to the designated line. My question is? How do I pass the string into the function, then loop around the string to send one charecter out at a time to the display. Below is a sample of my code. I think I am having a problem using pointers.


char str[20];
// String to pass into function
col=2;
char Header[17]={'M','S',' ','E','S','S',' ','C','o','n','t','r','o','l','l','e','r','0'};


Display_update_2( *header,col); // call to function

// Function
Void Display_update_2(*str, col)
{
int cntr;
char temp_str[20];
strcpy(*temp_str,*str);


//char *str;
/*
i2c_start () ; commented out so i can bypass I2C writes
i2c_write (disp_wrt) ;
i2c_write (71) ;
i2c_write (col); //col
i2c_write (2); //row
*/
while(*HEADER!= 0) ; // pointer method

// i2c_write (*HEADER) ;
*HEADER++;

//for(cntr=0;cntr<=strlen(&String_to_write);cntr++); // for/loop method
//{

//}
i2c_stop();


}

[Wayne_]

A few problems

The first is your sting is not a string but an array of chars, there is a difference. Your last char is '0' the character 0. A string is null terminated meaning the last char is a 0, not the character '0' but the actual value 0. Just remove the single quuotes around it.

You array is also 1 character short, it needs to be [18] for that paticualr string, must include the null terminating char.

The second is you use the pointer HEADER but this is not defined as such!

your routine should be

[armondo522]

Thanks Wayne for the reply,
When I do this

[FvM]

I see some type confusion in your code, the below snippet compiles without errors, you may want to use it as a starting point:

[armondo522]

Thanks for the help...works great..

[Wayne_]

You get the error
char header[18]; // get error numeric expression must appear here

most likely because all youe variable declarations need to be before any code is written within the scope of that var, so globals are declared before any function including main and locals are delared at the top of the function before any code!

I presume you already have some code before this line!