Update README.md

Author: alexgian1

README.md

@@ -11,6 +11,12 @@ The parser translates the input language into Java. It uses JavaCUP for the gene
 
 We assume that the program input will always be semantically correct. The input language the function declarations must precede all statements.
 
+## Execution
+
+- `make compile` : Compiles the required files for the parser. *(Requires **jflex**)*
+- `make execute` : Executes the main program that waits for input in stdin and uses the parser to return the Java code on stdout.
+- `make clean` : Removes all files generated by `make compile`.
+
 ## Input examples
 
 ### Example 1