I have a 2D array with 108 strings. How do I shuffle it correctly?
I don't think I'm doing it right
Code:void Shuffle( char dest[208][13] ) { // Initialize variables char temp[13]; // Loop and shuffle(swap array values) for (int i=208; i>1; i-- ) { int m = i + rand()%(208-i); strcpy(temp,dest[m]); // strcpy(dest[m],dest[i]); strcpy(dest[i],temp); cout << destination[i] << " "; }
The program force closes.
>char temp[13];
char temp[208];
The character array should be the same size as your strings can be.
Describe in words what is the purpose of line 9.
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
> The character array should be the same size as your strings can be.
It is.
The 208 is the major dimension, not the minor one (which is just 13, the same as the local).
> for (int i=208; i>1; i-- )
However, starting at 208 is an array overrun, since the max subscript is 207
> cout << destination[i] << " ";
OK, so where is the real code?
1. You're using cout in a C program. If this is really C++ then there are many things you should be doing differently, like using std::vector in place of arrays and std::string in place of char arrays.
2. There is no variable in scope called destination, so how did this even compile?
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
I;m not sure.Originally Posted by vart
And the destination in the cout is just a typo. Should be dest.
I haven't learn about std::vector or anything like that yet.
If you do not know where you want to get it is not important where you go.
If you do not know what your code should do - it is not important what it really does
All problems in computer science can be solved by another level of indirection,
except for the problem of too many layers of indirection.
– David J. Wheeler
I don't understand why line 9 is there. How about you just randomly generate two strings from the 207 strings and swap them? It's easier. (Maybe it takes longer time than the original method you were using, but then I don't really know what you were using, and you couldn't explain the purpose of line 9.)
