47 lines
790 B
C
47 lines
790 B
C
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/*
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Program: binary-search-solves-equation.c (Report comments/bugs to chikh@yuntech.edu.tw)
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Function: <EFBFBD>Q<EFBFBD>ΤG<EFBFBD><EFBFBD><EFBFBD>j<EFBFBD>M<EFBFBD>k<EFBFBD>D<EFBFBD><EFBFBD><EFBFBD>{<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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*/
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#include <stdio.h>
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#include <math.h>
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//#define f(x) (x)*(x)
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#define f(x) x+sin(x)-1
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//#define f(x) ((x)*exp(x))*((x)*exp(x))
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double binary_search(double);
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int main()
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{
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float value, answer;
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printf("Enter the value ==> ");
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scanf("%f",&value);
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answer = binary_search(value);
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printf("The root = %g (Check if f(%g)=%g == %g?)\n",answer,answer,f(answer),value);
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return 0;
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}
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double binary_search(double y)
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{
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double a, b, mid, temp;
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a = 0;
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b = y+2;
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while (1) {
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if (a > b) break;
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mid = (a+b)/2.0;
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temp = f(mid);
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if (fabs(temp-y) < 1e-10) return mid;
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if (temp < y)
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a = mid;
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else
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b = mid;
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}
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return -1;
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}
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