【额外练习】选择结构

【额外练习】选择结构/7-48 选择-三角形面积2.c

@@ -0,0 +1,24 @@
+#include <math.h>
+#include <stdio.h>
+
+int main() {
+    int x1, y1, x2, y2, x3, y3;
+    double a, b, c, s, area;
+
+    scanf("%d%d%d%d%d%d", &x1, &y1, &x2, &y2, &x3, &y3);
+
+    a = sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
+    b = sqrt((x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3));
+    c = sqrt((x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3));
+
+    if (a + b > c && a + c > b && b + c > a) {
+        s = (a + b + c) / 2;
+        area = sqrt(s * (s - a) * (s - b) * (s - c));
+
+        printf("%.1f %.1f\n", a + b + c, area);
+    } else {
+        printf("no triangle!\n");
+    }
+
+    return 0;
+}

【额外练习】选择结构/7-58 选择-汉笨笨拜师3.c

@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <string.h>
+
+char a[3], b[3];
+
+int main() {
+    scanf("%s%s", a, b);
+
+    if (a[0] == 'J') {
+        strcpy(a, "11");
+    } else if (a[0] == 'Q') {
+        strcpy(a, "12");
+    } else if (a[0] == 'K') {
+        strcpy(a, "13");
+    } else if (a[0] == 'A') {
+        strcpy(a, "14");
+    } else if (a[0] == '2') {
+        strcpy(a, "15");
+    }
+
+    if (b[0] == 'J') {
+        strcpy(b, "11");
+    } else if (b[0] == 'Q') {
+        strcpy(b, "12");
+    } else if (b[0] == 'K') {
+        strcpy(b, "13");
+    } else if (b[0] == 'A') {
+        strcpy(b, "14");
+    } else if (b[0] == '2') {
+        strcpy(b, "15");
+    }
+
+    int a1 = a[0] - '0', a2 = a[1] - '0';
+    int b1 = b[0] - '0', b2 = b[1] - '0';
+
+    int a0 = a2 * 10 + a1;
+    int b0 = b2 * 10 + b1;
+
+    if (a0 == b0) {
+        printf("No winner\n");
+    } else if (a0 > b0) {
+        printf("Alice win\n");
+    } else {  // a0 < b0
+        printf("Bob win\n");
+    }
+
+    return 0;
+}