黄金分割法求极值(c编程)

1、流程图:C程序：#include include double f(double x) double y;y=*x*x*x+;return (y);void mainOdouble a, b, xl, x2, w, s, min, xO;int i二1;double h;w=(sqrt (5)-l)/2;s=le-5;printf(z，input a, h： n，?);scanfC%lf,%lf/z,&a,&h)；do/*确定初始区域a,b*/b=a+i*h;i+；printf (?，i=%d, b二Lfn, i, b);while (f (a)f (b);xl=a+(l-w)*(b-a);x

2、2=a+w*(b-a);printf C %lf,玄If n, a, b);loop:辻(f (xl) f (x2)/*不断缩小区域，经n次迭代直至b-a |s)x2=xl;xl=a+(l-w)*(b-a);printf (xl=%lf, x2=%lfnzz, xl, x2);goto loop;else f(a+b)/2);elsea=xl;if (fabs (b-a) s)xl=x2;x2=a+w*(b-a);printf (xl=%lf, x2=%lfnzz, xl, x2);goto loop;else f(a+b)/2);x0=(a+b)/2;min=f (xO);printf (/

3、zxO=%lf, min=%lfn/，, (a+b) /2, f (a+b)/2);运算结果:C *C:Docuents and Settin； input a，h；-2,1i=2,b=-1.000000i=3,b=0.000000 i=4,b=1.000000 i=5,b=2.000000 -2000000,2 000000J xl=0.472136,x2=1.055728 xl=0.111456,x2=0.472136 xl=0.472136,x2=0.695048 xl=0.695048,x2=0.832816 xl=0.832816,x2=0.917961 xl=0.780193,x2

4、=0.832816 xl=0.832816,x2=0.865338 xl=0.81271G,x2=0.832816 xl=0.800293,x2=0.812716 xl 詡.812716,x2 =0.820393 xl=0 8 07971,x2=0.812716 xl 詡.81271G,x2 =0.815648 xl815648x2=0.817461 xl=0.814528x2=0.815648 xl8i5648zx2=0.816341 xl=0.816341r81649Sin =0.666667 Press any key to continueK C: Docuents and Sett i: input 2.1 i=2,b=3.0000002Q&2000025 xl=2.000010,x2=2.000016 xl=200000