mapOf / mutableMapOf

var map = mapOf("user1" to "pass1" , "user2" to "pass2")
for ( (key,value) in map ) {
    printIn("keyは${key}")
    printIn("valueは${value}")
}

var map = mutableMapOf("user1" to "pass1", "user2" to "pass2")
map.put("user3" to "pass3")
for ( (key,value) in map ) {
    printIn("${key}")
    printIn("${value}")
}