Golang sum counter by Mikhalich

sum.go

@@ -0,0 +1,62 @@
+package main
+
+import "fmt"
+import "runtime"
+
+// COPYLEFT MIKHALIdCH 2018
+
+func sum_chunk(first int, last int, channel chan int) {
+
+  //fmt.Println("performing summ", first, last)
+  result := 0
+  for last >= first {
+    num := last
+    digit := 0
+    for num > 0 {
+      digit = num % 10
+      result = result + digit
+      num = num / 10
+    }
+    last--
+  }
+    //fmt.Println(result)
+    channel <- result
+}
+
+
+func main() {
+  // need to change it to getting from args
+  var first, last int = 0, 1000000000
+  //fmt.Scanln(&first, "enter first value")
+  //fmt.Scanln(&last, "enter last value")
+  fmt.Println("Processing sequence from", first, "to", last)
+  nprocs := runtime.NumCPU()
+  //nprocs = 1
+  runtime.GOMAXPROCS(nprocs)
+  if last <= nprocs {
+    nprocs = 1
+  }
+  var shard, remainder int
+    shard = last / nprocs
+    fmt.Println("Shard size:", shard)
+    remainder = last % nprocs
+    fmt.Println("remainder:", remainder)
+    channel := make(chan int)
+
+  for i := first ; i < last ; i = i + shard {
+        if i > last - shard {
+             fmt.Println(i, last)
+              go sum_chunk(i, last, channel)
+         } else {
+              fmt.Println(i, i + shard)
+              go sum_chunk(i, i + shard, channel)
+              i+=1
+         }
+    }
+
+    result := 0
+    for j := 0 ; j < nprocs ; j++ {
+      result += <-channel
+    }
+    fmt.Printf("Result: %v\n", result)
+}