程序代码：

# define M 510
#include <stdio.h>
#include <math.h>
main()
{
    double x, T, a, j1, j2, x1, y1, x2, y2, x3, y3, x4, y4, j;
    double i, c;
    double f(double,double,double,double,double,double,double,double,double);
    j1 = 52;
    j2 = 40;
    j = 50;
    printf("请输入扭矩稳定时的最低点的数值:\n");
    scanf("%lf,%lf",&T,&a);
    printf("请输入您的瞬时扭矩的数值:\n");
    fflush(stdin);
    printf("请输入4个初始点:\n");
    scanf("%lf,%lf,%lf,%lf,%lf,%lf,%lf,%lf", &x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4);
    if (T < a) {
        x = x1;
        c = 10;
        while (c >= 0.5) {
            c = fabs(f(x, x1, y1, x2, y2, x3, y3, x4, y4) - T);
            x++;
        };
        c = f(x++, x1, y1, x2, y2, x3, y3, x4, y4);
        i = 1.5 * (M - j * (j1 - j2) * 1.0 / c);
        printf("这是下一个时间段所对应的电流%f\n", i);
    }
    if (T >= a) {
        i = 1.5 * (M - j * (j1 - j2) * 1.0 / T);
        printf("这是下一个时间段所对应的电流%f\n", i);
    }
}
double f(double x, double x1, double y1, double x2,double y2, double x3, double y3, double x4, double y4)
{
    return (((x - x1) * (x - x2) * (x - x3)) / ((x4 - x1) * (x4 - x2) * (x4 - x3)) * y4 + ((x - x1) * (x - x2) * (x - x4)) / ((x3 - x1) *
                 (x3 - x2) * (x3 - x4)*y3 + ((x - x1) * (x - x4) * (x - x3)) / ((x2 - x1) * (x2 -x4) * (x2 - x3)) *y2 + ((x - x4) *
                 (x - x2) * (x - x3)) / ((x1 - x4) * (x1 - x2) * (x1 - x3)) * y1);
}