rust implementation

1 files changed, 35 insertions, 0 deletions

diff --git a/DNA.rs b/DNA.rs
new file mode 100644
index 0000000..dc572e2
--- /dev/null
+++ b/DNA.rs
@@ -0,0 +1,35 @@
+use io::{stdin,println,ReaderUtil};
+
+fn count_nucleotides(dna: &str) -> (int, int, int, int) {
+    let mut (a, c, g, t) = (0, 0, 0, 0);
+    for str::each_char(dna) |ch| {
+        match ch {
+            'A' => a += 1,
+            'C' => c += 1,
+            'G' => g += 1,
+            'T' => t += 1,
+            _   => fail ~"Unexpected character found"
+        }
+    }
+    (a, c, g, t)
+}
+
+fn count_nucleotides_2(dna: &str) -> (int, int, int, int) {
+    do iter::foldl(&str::chars(dna), (0, 0, 0, 0)) |res, &ch| {
+        let (a, c, g, t) = *res;
+        match ch {
+            'A' => (a + 1, c, g, t),
+            'C' => (a, c + 1, g, t),
+            'G' => (a, c, g + 1, t),
+            'T' => (a, c, g, t + 1),
+            _   => fail ~"Unexpected character found"
+        }
+    }
+}
+
+fn main() {
+    let dna = stdin().read_line();
+    let (a, c, g, t) = count_nucleotides(dna);
+    /*let (a, c, g, t) = count_nucleotides_2(dna);*/
+    println(fmt!("%d %d %d %d", a, c, g, t));
+}