What is the usage of Permuation and Combination in the real life or Computer Programming world? I have never understood the application of P & C, even in the software programming. I know, the principle behind P&C is counting. So, basically it makes the counting quicker. However, I could never apply it while programming,real life, etc? The only application I could find was very trivial - how many 2 digit binary numbers are possible? The answer is 00, 01, 10, 11. Since the numbers can repeat here - the answer is 2*2, which is 4. Apart from this, I couldn't find its application? Can someone please help me on it? This way, I can appreciate this topic in mathematics. 
As per the people comments - this question is quite vague. Thus, I am rewording it to - suffice it's need in programming world like - Embedded, Graphics, Business, etc

After doing a google - I found an interesting application -
http://walkinginmathland.weebly.com/teaching-math-blog/wendy 
