Suppose you want to store the movements of a chess game in a file so that when the program terminates, the users can resume it later from the same point. To enable this you need to store an array that contains each player’s movements in a file, for example:
for(int i=0; i
However, this approach is problematic because a program that reads from the file can't tell in advance how many elements exist in the stored array. A better solution is to write the number of elements before the first array element:
Likewise, when you read the array from the file, first read the number of elements and then read as many integers into your local array:
mystream>>n; // read number of elementsint *arr= new int(n); //for(int i=0; i
>arr[n]; // copy elements from file into arr
This simple protocol enables you to store several arrays in a file. Before you read each array, read the number of its elements and then read as many elements in a loop. Repeat this process until you've reached the EOF sign.