Variable string array

Hi,
I want to make a string array of variable length x. Now for every index of the array i want the value to be increasing like below:
string[x] arry;
arry[0] = " ";
arry[1] = "  ";
arry[2] = "   ";
arry[3] = "    ";
and so o till x............ so how to make it?????
 
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