golang信号SIGSEGV：分段违规

huangapple
go评论109阅读模式
英文:

golang signal SIGSEGV: segmentation violation

问题

我正在尝试在Go语言中使用高阶函数。在包含"result := calcFunction(radius)"的行中，printResult函数发生了panic。有人可以帮我看看我在这里做错了什么吗？

  1. package main
  3. import "fmt"
  5. func calcArea(r float64) float64 {
  6. 	return 3.14 * r * r
  7. }
  9. func calcPerimeter(r float64) float64 {
  10. 	return 2 * 3.14 * r
  11. }
  13. func calcDiameter(r float64) float64 {
  14. 	return 2 * r
  15. }
  17. func getFunction(query int) func(r float64) float64 {
  18. 	query_to_func := map[int]func(r float64) float64{
  19. 		1: calcArea,
  20. 		2: calcPerimeter,
  21. 		3: calcDiameter,
  22. 	}
  23. 	return query_to_func[query]
  24. }
  26. func printResult(radius float64, calcFunction func(r float64) float64) {
  27. 	result := calcFunction(radius)
  28. 	fmt.Println("Result:", result)
  29. }
  31. func main() {
  32. 	var query int
  33. 	var radius float64
  35. 	fmt.Print("Enter the radius of the circle: ")
  36. 	fmt.Scanf("%f", &radius)
  37. 	fmt.Print("Enter operation: \n 1: Area\n 2: Perimeter\n 3: Diameter \n :")
  38. 	fmt.Scanf("%d", &query)
  39. 	printResult(radius, getFunction(query))
  40. }

你可以尝试将fmt.Scanf("%f", &query)改为fmt.Scanf("%d", &query)，因为query是一个整数，而不是浮点数。这可能是导致panic的原因。

英文:

I am trying higher order function in golang. It is panicking in printResult function at line containing "result := calcFunction(radius)". Can anybody help me as what I am doing wrong here.

  1. package main
  3. import "fmt"
  5. func calcArea(r float64) float64 {
  6. 	return 3.14 * r * r
  7. }
  9. func calcPerimeter(r float64) float64 {
  10. 	return 2 * 3.14 * r
  11. }
  13. func calcDiameter(r float64) float64 {
  14. 	return 2 * r
  15. }
  17. func getFunction(query int) func(r float64) float64 {
  19. 	query_to_func := map[int]func(r float64) float64{
  20. 		1: calcArea,
  21. 		2: calcPerimeter,
  22. 		3: calcDiameter,
  23. 	}
  24. 	return query_to_func[query]
  26. }
  28. func printResult(radius float64, calcFunction func(r float64) float64) {
  29. 	result := calcFunction(radius)
  30. 	fmt.Println("Result:", result)
  31. }
  33. func main() {
  34. 	var query int
  35. 	var radius float64
  37. 	fmt.Print("Enter the radius of the circle: ")
  38. 	fmt.Scanf("%f", &radius)
  39. 	fmt.Print("Enter operation: \n 1: Area\n 2: Perimeter\n 3: Diameter \n :")
  40. 	fmt.Scanf("%f", &query)
  41. 	printResult(radius, getFunction(query))
  43. }

答案1

得分: 3

问题出在fmt.Scanf("%f", &query)这一行。query是int类型，而你正在使用%f(float64)进行扫描。因此，值变为0。由于映射中没有该值，所以会引发错误。

  1. func main() {
  2.     var query int
  3.     var radius float64
  5.     fmt.Print("Enter the radius of the circle: ")
  6.     fmt.Scanf("%f", &radius)
  7.     fmt.Print("Enter operation: \n 1: Area\n 2: Perimeter\n 3: Diameter \n :")
  8.     fmt.Scanf("%d", &query)
  9.     printResult(radius, getFunction(query))
  10. }
英文:

Problem is with the fmt.Scanf("%f", &query). query is int and you are scanning to %f(float64). So the value become 0. Since map does not have that value, it panics.

  1. func main() {
  2. 	var query int
  3. 	var radius float64
  5. 	fmt.Print("Enter the radius of the circle: ")
  6. 	fmt.Scanf("%f", &radius)
  7. 	fmt.Print("Enter operation: \n 1: Area\n 2: Perimeter\n 3: Diameter \n :")
  8. 	fmt.Scanf("%d", &query)
  9. 	printResult(radius, getFunction(query))
  10. }
  12. </details>

huangapple
  • 本文由 发表于 2022年3月14日 12:59:21
  • 转载请务必保留本文链接：https://go.coder-hub.com/71463164.html
  • go
  • segmentation-fault
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