This topic is about Solidity – For Loop.
The for loop is the most compact form of looping. It includes the following three important parts −
- The loop initialization where we initialize our counter to a starting value. The initialization statement is executed before the loop begins.
- The test statement which will test if a given condition is true or not. If the condition is true, then the code given inside the loop will be executed, otherwise the control will come out of the loop.
- The iteration statement where you can increase or decrease your counter.
You can put all the three parts in a single line separated by semicolons.
Flow Chart
The flow chart of a for loop in Solidity would be as follows −
Syntax
The syntax of for loop is Solidity is as follows −
for (initialization; test condition; iteration statement) {
Statement(s) to be executed if test condition is true
}
Example
pragma solidity ^0.5.0;
contract SolidityTest {
uint storedData;
constructor() public{
storedData = 10;
}
function getResult() public view returns(string memory){
uint a = 10;
uint b = 2;
uint result = a + b;
return integerToString(result);
}
function integerToString(uint _i) internal pure
returns (string memory) {
if (_i == 0) {
return "0";
}
uint j=0;
uint len;
for (j = _i; j != 0; j /= 10) { //for loop example
len++;
}
bytes memory bstr = new bytes(len);
uint k = len - 1;
while (_i != 0) {
bstr[k--] = byte(uint8(48 + _i % 10));
_i /= 10;
}
return string(bstr);//access local variable
}
}
Run the above program using steps provided in Solidity First Application chapter.
Output
0: string: 12
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