What is the output of int a = 10; printf("%d", a << 2);?

The output of the given code will be 40.

Here's the step by step explanation:

1. The code int a = 10; is declaring an integer variable 'a' and assigning it the value 10. In binary, 10 is represented as 1010.

2. The '<<' operator is a bitwise operator that shifts the bits of the number to the left by the number of bits specified. In this case, a << 2 shifts the bits of 'a' 2 places to the left.

3. When we shift the bits of 10 (1010 in binary) 2 places to the left, we get 101000, which is the binary representation of 40.

4. Finally, printf("%d", a << 2); prints the result of a << 2, which is 40.