DAY16
Monday, 18 June 2012

Today we will talk about:

• swapping, which interchanges the values of two variables.
• sorting, which rearranges a set of values so that they have an order.
• arrays, which allow you to set up, store, and compute with lists.
• rules for declaring an array variable, for initializing, using, or changing an entry in an array.
• examples of how arrays are used to store mathematical vectors; lists of grades; a sequence of Fibonacci numbers.

Programs and functions we might talk about:

• abc_max.c sets the entries A, B, C to random numbers (using iran.c), then finds the maximum.
• abc_sort.c sets the entries A, B, C to random numbers (using iran.c), then sorts them.
• abc_swap.c uses the idea of swapping to rearrange the entries A, B, C.
• array_max.c sets the entries of an array to random numbers (using iran.c), then finds the maximum.
• array_sum.c shows how to compute the sum of the elements of an (integer) array.
• grades.c uses an array to store up to 100 grades. It computes the average, and prints a summary of the grades by letter.
• grades.txt a file containing 53 grades, followed by a "-1" to signal the end. The grading program can read this data, if you use a command like ./a.out < grades.txt.
• iran.c returns random integers in some interval.
• p7.1.c shows how the elements of an array can be used in expresssions. (This is an example program from the book.)
• p7.3.c computes an array whose entries are Fibonacci numbers: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, ... (This is an example program from the book.)
• vector.c considers three vectors in 3D space, and finds their lengths, dot products, pairwise cosines and angles.