cls03

src/cls03/Makefile

@@ -0,0 +1,14 @@
+include ../common.mk
+
+PROJECT_NAME:=cls03
+
+TGTS:=$(patsubst %.c,%,$(wildcard *.c))
+
+all: $(TGTS)
+
+%: %.c
+	@mkdir -p $(BUILD_PATH)/$(PROJECT_NAME)
+	$(CC) $(CFLAGS) -I. $^ -o $(BUILD_PATH)/$(PROJECT_NAME)/$@
+
+clean:
+	$(RM) -drf $(BUILD_PATH)/$(PROJECT_NAME)

src/cls03/a1.c

@@ -0,0 +1,19 @@
+#include <stdio.h>
+
+unsigned int sum_recc(unsigned int n) {
+    if (n == 0) return 0;
+    return n + sum_recc(n - 1);
+}
+
+int main(void) {
+    unsigned int x = 0;
+
+    printf("Input natural number: ");
+    (void)scanf("%u", &x);
+
+    unsigned int s = sum_recc(x);
+
+    printf("Result: %u\n", s);
+
+    return 0;
+}

src/cls03/a2-4.c

@@ -0,0 +1,58 @@
+#include <stdio.h>
+
+void getTwoInts(int* a, int* b) {
+    printf("1st Int: ");
+    (void)scanf("%d", a);
+    printf("2nd Int: ");
+    (void)scanf("%d", b);
+}
+
+void printRatio(int r[]) {
+    printf("%d/%d", r[0], r[1]);
+}
+
+int gcm(int a, int b);
+int lcm(int a, int b);
+void reduce(int x[]);
+
+int gcm(int a, int b) {
+    int x = a, y = b;
+    if (x < y) {
+        x = b;
+        y = a;
+    }
+    int r = a % b;
+    if (r == 0) return b;
+    return gcm(b, r);
+}
+
+int lcm(int a, int b) {
+    int g = gcm(a, b);
+    return b * a / g;
+}
+
+void reduce(int x[]) {
+    int a = x[0], b = x[1];
+    int g = gcm(a, b);
+    x[0] = a / g;
+    x[1] = b / g;
+}
+
+int main(void) {
+    int a,b;
+
+    getTwoInts(&a, &b);
+    int g = gcm(a, b);
+    int l = lcm(a, b);
+
+    printf("Result:\ngcm = %d\nlcm = %d\n", g, l);
+
+    int r[2] = {a, b};
+    printf("Before: ");
+    printRatio(r); putchar('\n');
+    reduce(r);
+    printf("After: ");
+    printRatio(r); putchar('\n');
+
+    return 0;
+}