public/subjects/countif.en.md

## countif

### Instructions

Write a function `CountIf` that returns the number of elements of a `string` array for which the `f` function returns `true`.

### Expected function

```go
func CountIf(f func(string) bool, tab []string) int {
}
```

### Usage

Here is a possible [program](TODO-LINK) to test your function :

```go
package main

import (
	"fmt"
	piscine ".."
)

func main() {
	tab1 := []string{"Hello", "how", "are", "you"}
	tab2 := []string{"This","1", "is", "4", "you"}
	answer1 := piscine.CountIf(piscine.IsNumeric, tab1)
	answer2 := piscine.CountIf(piscine.IsNumeric, tab2)
	fmt.Println(answer1)
	fmt.Println(answer2)
}
```

And its output :

```console
student@ubuntu:~/piscine/test$ go build
student@ubuntu:~/piscine/test$ ./test
0
2
student@ubuntu:~/piscine/test$
```