// tolowercase
package main
import (
"fmt"
)
func isValidAlph(s string) bool {
return s >= "A" && s <= "Z"
}
func toLowerCase(str string) string {
ret := ""
for _, value := range str {
ch := fmt.Sprintf("%c", value)
if isValidAlph(ch) {
value = value + 'a' - 'A'
ret += fmt.Sprintf("%c", value)
} else {
ret += ch
}
}
return ret
}
func main() {
fmt.Println(toLowerCase("He9llo"))
}
![8982195-d47645f52d35b39e.png](https://upload-images.jianshu.io/upload_images/8982195-d47645f52d35b39e.png)
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