根據題意可得代碼如下:
#include?<math.h>
const?double?pi=3.14159265;
int?main()
{
double?a,?b,?C,?c;
printf?("請輸入兩邊長度及其夾角(角度):");
scanf?("%lf%lf%lf",?&a,?&b,?&C);
c?=?sqrt(a*a+b*b-2*a*b*cos(C*pi/180));
printf?("第三邊的長度為:%f\n",?c);
return?0;
}