In an effort to attract more — and more diverse — programmers, the CEOs of two dozen big tech companies, including Microsoft , Google and Salesforce.com, will launch a campaign Wednesday with non-profit Code.org to introduce computer science to 100 million students world-wide. The companies agreed to promote Hour of Code, a campaign that encourages students to try an hour of computer coding with an online tutorial. They also plan a crowd-sourced campaign to raise $5 million to be used to train teachers in schools that don’t offer computer science classes, Code.org said. The companies will ask employees to support the Hour of Code during Computer Science Education Week in December, by trying the tutorials, encouraging students to take the online course, and donating to the campaign. Roughly 40 million people have participated in Hour of Code since the program started last year, some of them taught by Facebook founder Mark Zuckerberg and Microsoft co-founder Bill Gates.