There was a left over.

programs/abs-floating/main.c

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+#include <stdio.h>
+
+int main(void) {
+    double x, y;
+
+    printf("Input floating point: ");
+    scanf("%lf", &x);
+
+    y = x;
+
+    if (y < 0.0)
+        y = -y;
+
+    printf("Absolute value of %lf is %lf.\n", x, y);
+
+    return 0;
+}