Fixed standard input error handling

pkg/pointer/intput-output.go

@@ -2,37 +2,42 @@ package pointer
 
 import (
 	"fmt"
-	"log"
 	"os"
 )
 
 var defaultInputLastChar *int = nil
 
-func DefaultCharacterInput() int {
+func DefaultCharacterInput() (int, error) {
 	if defaultInputLastChar != nil {
 		c := *defaultInputLastChar
 		defaultInputLastChar = nil
-		return c
+		return c, nil
 	}
 	b := make([]byte, 1)
 	i, err := os.Stdin.Read(b)
 	if err != nil {
-		log.Fatalf("Error in DefaultCharacterInput { b: %c, i: %d, err: %+v }", b[0], i, err)
+		return 0, fmt.Errorf("Error in DefaultCharacterInput { b: %c, i: %d, err: %w }", b[0], i, err)
 	}
-	return int(b[0])
+	return int(b[0]), nil
 }
 
-func DefaultDecimalInput() int {
+func DefaultDecimalInput() (int, error) {
 	var v int
 	for {
-		c := DefaultCharacterInput()
+		c, err := DefaultCharacterInput()
+		if err != nil {
+			return 0, err
+		}
 		if c >= '0' && c <= '9' {
 			v = c - '0'
 			break
 		}
 	}
 	for {
-		c := DefaultCharacterInput()
+		c, err := DefaultCharacterInput()
+		if err != nil {
+			break
+		}
 		if c >= '0' && c <= '9' {
 			v = v*10 + c - '0'
 		} else {
@@ -40,7 +45,7 @@ func DefaultDecimalInput() int {
 			break
 		}
 	}
-	return v
+	return v, nil
 }
 
 func DefaultCharacterOutput(c int) {