Design to Programming

1. Design to Programming • The translation from design to program must be more or less a mechanical process except for implementer’s decisions • This will ensure consistency between design and program • A program must include every information from its design and can add more, but nothing must be left out • Programming language-specific information can be included but must be properly documented • E.g.,use of built-in data types or classes Lecture 8

2. Choices to the implementer • Choose an effective algorithm, if not already requested by the designer • Keep sequence of elements sorted all the time, if not already requested by the designer • Grouping or packaging of classes for programming convenience • Change of data types from design to implementation for efficiency or compatibility purposes • Must be documented properly so that maintenance would be easier • Use of appropriate system calls Lecture 8

3. What is considered to be good program? • Adequate documentation • Include documentation for every class in its header, explaining class in its entirety • Must include author(s), date created, date modified, etc. • Include documentation for every method in its header, explaining the purpose of the method • Include documentation for every critical section of code (loops, if or case structure etc.) indicating the important decisions or branches Lecture 8

4. What is considered to be a good program? • Use of meaningful names for classes, methods, variables etc. • E.g. in an ATM system • ‘ATM’,’Account’,’Customer’,… are meaningful class names as opposed to ‘Acct’,’Cust’,’ATMach’ • ‘Deposit’,’Withdraw’,… are meaningful method names as opposed to ‘depo’, ‘with’,… • Organizational policy may influence the naming convention in a program, but still the programmer has more freedom • E.g., ‘_Mdeposit’ for deposit Lecture 8

5. What is considered to be a good program? • Well-structured program that is readable and understandable • Indentation makes a big difference in readability and understandability • Size of a method, number of parameters also plays a crucial role in this context • Strictly follow the programming language principles • Using a “break” statement inside a “for” loop? Lecture 8

6. Identify what the following code does public static void something(int[] array) { int i,j=array.length-1; int tmp, max = array.length/2; for(i=0;i<j;i++,j--) { if(array[max] <array[i]){ tmp =array[max]; array[max]=array[i]; array[i]=tmp; } if(array[max] <array[j]){ tmp = array[max]; array[max] = array[j]; array[j] = tmp; } } } Lecture 8

7. Identify what this code does public static iDontKnow(int[] array) { int i, j, tmp; for(i=1;i<array.length;i++) if(array[i]<array[i-1]) { tmp =array[i]; for(j=i-1;j>=0;j--){ array[j+1] = array[j]; if(j==0 || array[j-1]<tmp) break; } array[j]=tmp; } } Lecture 8