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？
package main
import "fmt"
func calcArea(r float64) float64 {
return 3.14 * r * r
}
func calcPerimeter(r float64) float64 {
return 2 * 3.14 * r
}
func calcDiameter(r float64) float64 {
return 2 * r
}
func getFunction(query int) func(r float64) float64 {
query_to_func := map[int]func(r float64) float64{
1: calcArea,
2: calcPerimeter,
3: calcDiameter,
}
return query_to_func[query]
}
func printResult(radius float64, calcFunction func(r float64) float64) {
result := calcFunction(radius)
fmt.Println("Result:", result)
}
func main() {
var query int
var radius float64
fmt.Print("Enter the radius of the circle: ")
fmt.Scanf("%f", &radius)
fmt.Print("Enter operation: \n 1: Area\n 2: Perimeter\n 3: Diameter \n :")
fmt.Scanf("%d", &query)
printResult(radius, getFunction(query))
}
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.
package main
import "fmt"
func calcArea(r float64) float64 {
return 3.14 * r * r
}
func calcPerimeter(r float64) float64 {
return 2 * 3.14 * r
}
func calcDiameter(r float64) float64 {
return 2 * r
}
func getFunction(query int) func(r float64) float64 {
query_to_func := map[int]func(r float64) float64{
1: calcArea,
2: calcPerimeter,
3: calcDiameter,
}
return query_to_func[query]
}
func printResult(radius float64, calcFunction func(r float64) float64) {
result := calcFunction(radius)
fmt.Println("Result:", result)
}
func main() {
var query int
var radius float64
fmt.Print("Enter the radius of the circle: ")
fmt.Scanf("%f", &radius)
fmt.Print("Enter operation: \n 1: Area\n 2: Perimeter\n 3: Diameter \n :")
fmt.Scanf("%f", &query)
printResult(radius, getFunction(query))
}
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。
func main() {
var query int
var radius float64
fmt.Print("Enter the radius of the circle: ")
fmt.Scanf("%f", &radius)
fmt.Print("Enter operation: \n 1: Area\n 2: Perimeter\n 3: Diameter \n :")
fmt.Scanf("%d", &query)
printResult(radius, getFunction(query))
}
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.
func main() {
var query int
var radius float64
fmt.Print("Enter the radius of the circle: ")
fmt.Scanf("%f", &radius)
fmt.Print("Enter operation: \n 1: Area\n 2: Perimeter\n 3: Diameter \n :")
fmt.Scanf("%d", &query)
printResult(radius, getFunction(query))
}
</details>
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