【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

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+#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;
+}