CitiusTech Senior Software Engineer interview questions

1st round they asked me some basic technical coding questions like printing the given list (array) numbers which are present in the odd number indexes. In the second round they gave a sentence and asked to find the occurrence of each letter and space count should not be considered, asked about previous company's project experience and questions based on that. Asked about agile methodology. HR round was basically about explaining the hybrid mode and salary expectations

Explain the OOPS with real time example