📝 Added sandbox (code sketchbook)

sandbox/sprintf.c

@@ -0,0 +1,13 @@
+/* https://www.tutorialspoint.com/c_standard_library/c_function_sprintf.htm */
+
+#include <stdio.h>
+#include <math.h>
+
+int main() {
+    char str[80];
+
+    sprintf(str, "Value of Pi = %f", M_PI);
+    puts(str);
+
+    return(0);
+}