How to assign array of pointers to pointers, to content of static array?

tommy00b · 06-30-2009, 06:38 PM

Code:

char myData[90][3][50];   //90 rows, 3 columns, each block 50 chars long   
char **tableData[90] = {NULL};  

const char* text;
text = sqlite3_column_text(stmt, col_index);

text_lenght = strlen(text) + 1;         // add 1 to get null 
strncpy(myData[row_index][c_index], text, text_lenght);
//top line in a loop for all rows and each column    <--EDIT the assignment is outside the column loop within the row loop.


tableData[row_index] = myData[row_index]; <--?Warning on this line

I need tableData to correctly point to contents of myData but it's not happening.
The warning is:

Code:

 : warning C4047: '=' : 'char ** ' differs in levels of indirection from 'char (*)[50]'

During run time I can see myData properly populated how I expect. However, tableData is filled with bad pointers...

Any help is appreciated.
Thanks.

tabstop · 06-30-2009, 06:55 PM

You need to assign every element of tableData to point where you want it to point.

tommy00b · 06-30-2009, 07:12 PM

I moved the assignment inside the column loop that is within the row loop and I believe this assigns each element, correct?

Code:

tableData_gmti[row_index][c_index]= myData_gmti[row_index][c_index];

No warnings but now I have the runtime error:

Code:

Unhandled exception at 0x0040308e in GUI.exe: 0xC0000005: Access violation writing location 0x00000000.

Sebastiani · 06-30-2009, 07:29 PM

>> I need tableData to correctly point to contents of myData but it's not happening.

That will never work because 'myData' isn't an array of pointers.

Code:

int main( int argc, char** argv )
{
	const int 
		ROW_COUNT = 90, 
		COLUMN_COUNT = 25, 
		TEXT_LENGTH = 50;
	typedef char 
		text_block[TEXT_LENGTH];
	typedef text_block 
		columns[COLUMN_COUNT];
	typedef columns
		table[ROW_COUNT] ;
	table 
		myTable; 
	columns*	
		myColumns[ROW_COUNT] = {0};
	myColumns[8] = &myTable[15];
	strncpy(myTable[15][4], "foobar", TEXT_LENGTH - 1);
	puts((*myColumns[8])[4]); 	
}

itCbitC · 07-01-2009, 01:53 PM

Quote:

Originally Posted by tommy00b

Code:

char myData[90][3][50];   //90 rows, 3 columns, each block 50 chars long   
char **tableData[90] = {NULL};  
...
tableData[row_index] = myData[row_index]; <--?Warning on this line

I need tableData to correctly point to contents of myData but it's not happening.

Perhaps something like

Code:

    char *a[50];
    char md[90][3][50];
    char **td[90] = {NULL};  
    a[0] = md[0][0];
    td[0] = &a[0];

06-30-2009, 06:55 PM	#2
tabstop and the Hat of Guessing Join Date: Nov 2007 Posts: 8,740	You need to assign every element of tableData to point where you want it to point.
tabstop is offline

06-30-2009, 07:12 PM	#3
tommy00b Registered User Join Date: Jun 2009 Posts: 2	Assigning each element runtime error I moved the assignment inside the column loop that is within the row loop and I believe this assigns each element, correct? Code: tableData_gmti[row_index][c_index]= myData_gmti[row_index][c_index]; No warnings but now I have the runtime error: Code: Unhandled exception at 0x0040308e in GUI.exe: 0xC0000005: Access violation writing location 0x00000000.
tommy00b is offline

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