What is the output of the following code?char str[] = "hello";int len = strlen(str);printf("%d\n", len);

The output of the code will be 5.

Here's the step by step explanation:

1. The char str[] = "hello"; line declares a character array str and initializes it with the string "hello".

2. The int len = strlen(str); line declares an integer len and initializes it with the length of the string str. The strlen function returns the length of a string (not including the null character at the end), so in this case it will return 5 because "hello" has 5 characters.

3. The printf("%d\n", len); line prints the value of len, which is 5, followed by a newline character. So the output of the code will be 5.