Solidity: How to use the pure getter and view functions?

Solidity provides two particular types of getter functions: view and pure.

The view functions

view allows the state to be read but does not allow the state to be modified:

uint public a = 1;
function viewFunction(uint b) public view returns (uint) {
  return a + b;
}

Let’s compile and deploy the contract. Then call the viewFunction() function:

The result is 3 = 1 + 2.

The view functions therefore ensure that they will not modify the state. The following statements modify the state:

• Modify a state variable,
• Emit an event,
• Create a contract,
• Use self-destruct,
• Send Ether via a call,
• Call a function that is not marked view or pure,
• Use a low level call,
• Use an inline assembly containing some opcodes.

Getter methods are by default view functions.

The pure functions

pure forbids the reading or modification of the state :

function pureFunction(uint x, uint y) public pure returns (uint) {
  return x + y;
}

Let’s compile and deploy the contract. Then call the pureFunction() function: