func countWhitespaceCharacters(_ str: String) -> Int {
var count = 0
for ch in str {
if ch.isWhitespace {
count += 1
}
}
return count
}
let str = "Swift \n Programming \r Language \t "
print("Total white spaces: \(countWhitespaceCharacters(str))")
/*
run:
Total white spaces: 10
*/