Code has been added to clipboard!
Storing Data With Solidity
Example
pragma solidity >=0.4.0 <0.7.0;
contract C {
uint[] x;
function f(uint[] memory memoryArray) public {
x = memoryArray; // works, copies the whole array to storage
uint[] storage y = x; // works, assigns a pointer, data location of y is storage
y[7]; // fine, returns the 8th element
y.length = 2; // fine, modifies x through y
delete x; // fine, clears the array, also modifies y
// The following does not work; it would need to create a new temporary /
// unnamed array in storage, but storage is "statically" allocated:
// y = memoryArray;
// This does not work either, since it would "reset" the pointer, but there
// is no sensible location it could point to.
// delete y;
g(x); // calls g, handing over a reference to x
h(x); // calls h and creates an independent, temporary copy in memory
}
function g(uint[] storage) internal pure {}
function h(uint[] memory) public pure {}
}