The code creates a while loop that allows the user to input the boundaries of a graphical representation of a mathematical function and plot it with contours.
Inside the while loop, the input values are assigned to variables 'xstart', 'xend', 'ystart', and 'yend'.
The 'linspace' function is used to create a vector x of 60 equally spaced points between 'xstart' and 'xend', and a vector y of 60 equally spaced points between 'ystart' and 'yend'.
The 'meshgrid' function returns 2-D grid coordinates based on the coordinates contained in vectors x and y. X is a matrix where each row is a copy of x, and Y is a matrix where each column is a copy of y. The grid represented by the coordinates X and Y has length(y) rows and length(x) columns.
After f and g functions return Z1 and Z2, the 'contour' function is used to plot the contour lines of Z1 and Z2 where the contour level is 0 (contour lines are drawn at a single height- 0).
The 'm' and 'b' arguments specify the colors of the contour lines.
For detailed explanation about ‘contour' and 'meshgrid' functions, please refer to the following documentation:
