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-rw-r--r--Tests/Tutorial/Step5/MathFunctions/mysqrt.cxx44
1 files changed, 44 insertions, 0 deletions
diff --git a/Tests/Tutorial/Step5/MathFunctions/mysqrt.cxx b/Tests/Tutorial/Step5/MathFunctions/mysqrt.cxx
new file mode 100644
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+++ b/Tests/Tutorial/Step5/MathFunctions/mysqrt.cxx
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+#include <stdio.h>
+#include "MathFunctions.h"
+#include "TutorialConfig.h"
+
+// include the generated table
+#include "Table.h"
+
+#include <math.h>
+
+// a hack square root calculation using simple operations
+double mysqrt(double x)
+{
+ if (x <= 0)
+ {
+ return 0;
+ }
+
+ double result;
+
+ // if we have both log and exp then use them
+ double delta;
+
+ // use the table to help find an initial value
+ result = x;
+ if (x >= 1 && x < 10)
+ {
+ result = sqrtTable[static_cast<int>(x)];
+ }
+
+ // do ten iterations
+ int i;
+ for (i = 0; i < 10; ++i)
+ {
+ if (result <= 0)
+ {
+ result = 0.1;
+ }
+ delta = x - (result*result);
+ result = result + 0.5*delta/result;
+ fprintf(stdout,"Computing sqrt of %g to be %g\n",x,result);
+ }
+
+ return result;
+}