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  1. #include <stdio.h>
  2. #include <math.h>
  3.  
  4. double f(double x) {
  5.     return x * x - 1.0 - sin(x);
  6. }
  7.  
  8. void bisection(double xl, double xr) {
  9.     double xi;
  10.     int count = 0;
  11.     while (1) {
  12.         xi = (xl + xr) / 2.0;
  13.         count++;
  14.         if (fabs(f(xi)) < 1e-5) break;
  15.  
  16.         if (f(xl) * f(xi) < 0) xr = xi;
  17.         else xl = xi;
  18.     }
  19.     printf("Bisection: x = %f (Iterations: %d)\n", xi, count);
  20. }
  21.  
  22. void falsePosition(double xl, double xr) {
  23.     double xi;
  24.     int count = 0;
  25.     while (1) {
  26.         // Linear interpolation formula
  27.         xi = (xl * f(xr) - xr * f(xl)) / (f(xr) - f(xl));
  28.         count++;
  29.         if (fabs(f(xi)) < 1e-5) break;
  30.  
  31.         if (f(xl) * f(xi) < 0) xr = xi;
  32.         else xl = xi;
  33.     }
  34.     printf("False Position: x = %f (Iterations: %d)\n", xi, count);
  35. }
  36.  
  37. int main() {
  38.     // Root 1 interval approx [-1, 0]
  39.     // Root 2 interval approx [1, 2]
  40.     printf("Finding root in [1, 2]:\n");
  41.     bisection(1.0, 2.0);
  42.     falsePosition(1.0, 2.0);
  43.  
  44.     return 0;
  45. }
  46.  
Success #stdin #stdout 0.01s 5280KB
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stdin
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Standard input is empty
stdout
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Finding root in [1, 2]:
Bisection: x = 1.409622 (Iterations: 16)
False Position: x = 1.409622 (Iterations: 9)
https://ideone.com/sFXZ3C
language:
C (gcc 8.3)
created:
3 hours ago
visibility:
public

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