1. 读取学生成绩单文件2. 存入数组， 第一列存3.依次根据成绩判定等级（60分以下D， 60-79C，80-90B，90-99A，100A+ ）并将等级结果存到对应的数组里学好，第二列存成绩，第三列留给等级4.请画出成绩等级分布图（2D），函数任选5.请画3D图，函数任选 6. 通过subplot,重画上面两个图，形成一个合成图，上下分布-Read student transcr ipt file into an array, the first column of memory 3 the basis of merit in turn determine the level (less than 60 points D, 60-79C ,80-90B ,90-99A, 100A+) and grade results kept learn to a corresponding array, the second column deposit score, third column, left Level 4. draw grades maps (2D), the function optionally 5 Videos 3D plot, the function optionally 6 subplot redraw the above two figures, the formation of a synthetic figure, the upper and lower distribution