Initial data commit

Task/Approximate-equality/C/approximate-equality.c

@@ -0,0 +1,24 @@
+#include <math.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+bool approxEquals(double value, double other, double epsilon) {
+    return fabs(value - other) < epsilon;
+}
+
+void test(double a, double b) {
+    double epsilon = 1e-18;
+    printf("%f, %f => %d\n", a, b, approxEquals(a, b, epsilon));
+}
+
+int main() {
+    test(100000000000000.01, 100000000000000.011);
+    test(100.01, 100.011);
+    test(10000000000000.001 / 10000.0, 1000000000.0000001000);
+    test(0.001, 0.0010000001);
+    test(0.000000000000000000000101, 0.0);
+    test(sqrt(2.0) * sqrt(2.0), 2.0);
+    test(-sqrt(2.0) * sqrt(2.0), -2.0);
+    test(3.14159265358979323846, 3.14159265358979324);
+    return 0;
+}