esercizi 12 dic 2019

atrent/2019-12-12/Mem.go

+package main
+
+import (
+	"fmt"
+	"reflect"
+)
+
+func main() {
+  var s []int
+  //s=[]int{}
+  fmt.Println(s, len(s), cap(s), reflect.TypeOf(s))
+  if s == nil {
+    fmt.Println("nil!")
+  }
+}

atrent/2019-12-12/MultiSlice.go

+package main
+
+import "fmt"
+
+func main() {
+    // Create an empty slice of slices.
+    animals := [][]string{}
+    
+    // Create three string slices.
+    row1 := []string{"fish", "shark", "eel"}
+    row2 := []string{"bird"}
+    row3 := []string{"lizard", "salamander"}
+
+    // Append string slices to outer slice.
+    animals = append(animals, row1)
+    animals = append(animals, row2)
+    animals = append(animals, row3)
+
+    // Loop over slices in animals.
+    for i := range animals {
+        fmt.Printf("Row: %v\n", i)
+        fmt.Println(animals[i])
+    }
+}

atrent/2019-12-12/appendDelay.go

+//scrivere un programma che appenda elementi ad una slice, e che stampi a distanza di un intervallo di tempo
+//i vari valori che la slice assume nel tempo
+
+package main
+import (
+	"fmt"
+	"math/rand"
+	"time"
+)
+
+func main()  {
+	var s []int
+
+	now := time.Now().UnixNano()
+	rand.Seed(now)
+
+	//d,_=time.ParseDuration("1.5s")
+
+	//fmt.Println(s)
+
+	for i:=0; i<10000; i++ {
+		//n:=rand.Int()%100
+		s=append(s,155)
+
+		fmt.Print(len(s),cap(s),": ");
+		fmt.Println(time.Now().UnixNano()-now)
+		now = time.Now().UnixNano()
+	}
+}