Bill Gates was gracious about Steve Jobs' criticisms of him during an interview with Christiane Amanpour that aired Sunday on ABC News' "This Week."

In Walter Isaacson's just-released biography of Jobs, the Apple co-founder had criticized the Microsoft co-founder, saying Gates was unimaginative and had never invented anything.

In the interview with Amanpour, Gates said of Jobs: "Over the course of the 30 years we worked together, you know, he said a lot of very nice things about me and he said a lot of tough things. ... I respect Steve. We got to work together. We spurred each other on, even as competitors. None of that bothers me at all."

Gates speculated that some of Jobs' criticisms might have stemmed from frustration at Microsoft's marketplace success during the years that Apple struggled to gain market share with its premium-priced products.

Overall, Gates said, "Steve Jobs did a fantastic job. When you think about why is the world better today, the Internet, the personal computer, the phone, the way you can deal with information is just so phenomenal."

Amanpour's interview with Gates focused primarily on his mission to convince some of the wealthiest nations and corporations to aid poorer nations, ahead of the G20 economic summit next week in Cannes -- a mission made tougher by the current state of the world's economy.

Responding to a question from Amanpour about whether he buys the notion that there's class warfare going on in the U.S. right now, Gates said: "Fortunately there hasn't been class warfare. Warfare is where you're, like, shooting at each other, barricades in the street."

Here's video of Amanpour's interview with Gates, from ABC News: