This program reads in a string from standard input, and prints the string back out with upper- and lower-case characters reversed, followed by a newline. Specifics:
1. Our Y86 variant has no byte-oriented instructions. You will need to store each character in an integer-sized slot, i.e. four bytes.
2. You may assume that the string is less than or equal to 10 characters, plus a null byte.
3. The input will consist solely of a sequence from the characters a-z and A-Z, followed by a newline. The newline is not part of the string.
4. Upon receipt of the newline, input is done. The input string does not include the newline, and should be null-terminated. In other words, the string will take at most 11 * 4 = 44 bytes.
5. The program splits up naturally into a readstr(), a printstr(), and a mutate() function. You don’t have to do this, but note that readstr() and printstr() will be very useful in the third program, so it would pay to write them once and then copy them over.