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pragma solidity ^0.4.0;
// A variable which is declared will have an initial default value whose byte-representation
// is all zeros. The “default values” of variables are the typical “zero-state” of whatever
// the type is. For example, the default value for a bool is false. The default value for
// the uint or int types is 0. For statically-sized arrays and bytes1 to bytes32, each
// individual element will be initialized to the default value corresponding to its type.
// Finally, for dynamically-sized arrays, bytes and string, the default value is an
// empty array or string.
// A variable declared anywhere within a function will be in scope for the entire function,
// regardless of where it is declared. This happens because Solidity inherits its scoping
// rules from JavaScript. This is in contrast to many languages where variables are only
// scoped where they are declared until the end of the semantic block. As a result,
// the following code is illegal and cause the compiler to throw an error, Identifier already declared:
contract ScopingErrors {
function scoping() {
uint i = 0;
while (i++ < 1) {
uint same1 = 0;
}
while (i++ < 2) {
uint same1 = 0;// Illegal, second declaration of same1
}
}
function minimalScoping() {
{
uint same2 = 0;
}
{
uint same2 = 0;// Illegal, second declaration of same2
}
}
function forLoopScoping() {
for (uint same3 = 0; same3 < 1; same3++) {
}
for (uint same3 = 0; same3 < 1; same3++) {// Illegal, second declaration of same3
}
}
function foo() returns (uint) {
// baz is implicitly initialized as 0
uint bar = 5;
if (true) {
bar += baz;
} else {
uint baz = 10;// never executes
}
return bar;// returns 5
}
}
