Apart from the challenges of heterogeneity, business and social change and trust and security. Identify other problems and challenges that software engineering is likely to face in the 21st century (hint: think about the environment).

*write a program that defines symbolic names for several string literals (chars between quotes). * use each symbolic name in a variable definition. * use of symbolic to compose the assembly code instruction set can perform vara = (vara - varb) + (varc - vard); ensure that variable is in unsigned integer data type. * you should also further enhance your symbolic logic block to to perform expression by introducing addition substitution rule. vara = (vara+varb) - (varc+vard).