Add all the A tasks

Task/Arithmetic-Complex/C/arithmetic-complex-1.c

@@ -0,0 +1,32 @@
+#include <complex.h>
+#include <stdio.h>
+
+void cprint(double complex c)
+{
+  printf("%f%+fI", creal(c), cimag(c));
+}
+void complex_operations() {
+  double complex a = 1.0 + 1.0I;
+  double complex b = 3.14159 + 1.2I;
+
+  double complex c;
+
+  printf("\na="); cprint(a);
+  printf("\nb="); cprint(b);
+
+  // addition
+  c = a + b;
+  printf("\na+b="); cprint(c);
+  // multiplication
+  c = a * b;
+  printf("\na*b="); cprint(c);
+  // inversion
+  c = 1.0 / a;
+  printf("\n1/c="); cprint(c);
+  // negation
+  c = -a;
+  printf("\n-a="); cprint(c);
+  // conjugate
+  c = conj(a);
+  printf("\nconj a="); cprint(c); printf("\n");
+}