If the array has more levels, etc, those would need to be skipped. I somehow need to reliably loop through all items in the first level of the array that contain the category and subcategory info. Or this for example: => SimpleXMLElement Object Have a look at the C main function main (argc, argv) where argv are the parameters of the program and argc is their count. You have to pass the array size as an additional parameter or use std::vector and it's size method. The array that is returned by amazon looks like this: => SimpleXMLElement Object sizeof (anArray) returns the size of the type anArray, probably double. If it evaluates to true, the loop continues and the nested. In the beginning of each iteration, expr2 is evaluated. The syntax of a for loop is: The first expression ( expr1) is evaluated (executed) once unconditionally at the beginning of the loop. I have looked for other answers here that suggest the SimpleXML iterator for example, but that doesn't work and throws an exception because it could not be parsed as xml. for loops are the most complex loops in PHP. Thus the expression sizeof( *a ) will yield the size of the original array.I'm trying to loop over the browsenodes array the Amazon Product API returns for a requested product with ItemLookup but I can not figure out how to do it reliably since the returned array has always a different amount of levels. In this case dereferencing the pointer within the function you will get an object of the array type. You could determine the number of elements in an array if you pass a pointer to the whole array. Example: The other direction is possible too, with the aid of a function included at the bottom of this note. So you have to pass to the function explicitly also the number of elements in the array. arraychunk () is helpful when constructing tables with a known number of columns but an unknown number of values, such as a calendar month. Thus the expression sizeof( array ) / sizeof( int ) in general will always yield either 1 or 2. That size for example can be equal either to 4 or 8 depending on the used system. Then the expression sizeof( array ) will yield the size of the pointer itself that does not depend on whether the pointer points to a single object of the type int or to the first element of an integer array with a known number of elements in the array. If you have a pointer like this int *array If the array does not contain a known sentinel value (as for example character arrays that contain strings have as the sentinel value the terminating zero character '\0') then you can not find its end. In your case, you could consider 0 or -1 to signify the end of the array, but this convention must be used consistently by all callers of your function. The null byte ( \0) is used to tell the end of C strings, which are arrays of char. It is common to use a null pointer ( NULL) as such a sentinel for arrays of pointers, such as the char *argv argument of the main() function, but note that int argc is also provided to this function. The array could have a sentinel value as the last element of the array. The array could have a known fixed number of elements If this is not practical, there are different ways to infer the number of elements, relying on a convention that must be adhered to by the callers: The best approach for your function to get the number of elements is to provide it as a separate argument. In this case sizeof(array) evaluates to the size of the pointer, so dividing that by the size of an element is meaningless. sizeof(array) / sizeof(*array) only works for an actual array, not for a pointer, which is what a function receives as an argument, even if the array syntax is used in the function prototype. In C, there is no way to tell the number of elements in an array from a pointer to an element.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |