运用多线程的方法计算pi的值。通过公式法和面积法实现。可以通过调整线程数和数据的运算规模来计算pi，计算不同线程之间的性能差异。-Calculated using multi-threaded the value of pi. Area through the formula and method implementation. You can adjust the number of threads and data operations to calculate the size of pi

多线程计算pi的值，可以在程序开头更改线程数和N的值-Multi-threaded computing the value of pi, you can change the number of threads and the value of N at the beginning of the program

编写程序计算 PI 值 要求： ① 采用至少两种 线程分配方法； ② 使用时间函数统计每个线程的计算时间，对比分析哪种分配方法更优； ③ 程序调试及运行，输出运行结果。(Write programs to calculate PI values Requirements: 1.Use at least two kinds of thread allocation methods; 2.Use time function to calculate the computation ti