1  package piscine
 2  
 3  func ToUpper(s string) string {
 4  	r := []rune(s)
 5  	for i := range r {
 6  		if r[i] >= 'a' && r[i] <= 'z' {
 7  			r[i] = r[i] - 32
 8  		}
 9  	}
10  
11  	return string(r)
12  }