The for loop

One of the most famous and most used loops is the for loop, and we can use it in Solidity. The general structure of a for loop is as follows:

for (initialize loop counter; check and test the counter; increase the value of counter;) {
 Execute multiple instructions here
  }

for is a keyword in Solidity and it informs the compiler that it contains information about looping a set of instructions. It is very similar to the while loop; however it is more succinct and readable since all information can be viewed in a single line.

The following code example shows the same solution: looping through a mapping. However, it uses the for loop instead of the while loop. The i variable is initialized, incremented by 1 in every iterator, and checked to see whether it is less than the value of counter. The loop will stop as soon as the condition becomes false; that is, the value of i is equal to or greater than counter: