1-6个数字让三角形三边和相等

Question

最后一个判断条件
if（a+b+c==c+d+e&&a+b+c==a+f+e)然后运行得到了预期结果
但是我改成了
if（a+b+d==d+e+f&&a+b+d==a+c+f)却没有得到结果
不理解为什么abcdef的顺序不同影响结果

Answer 1

供参考：

#include<stdio.h>
int main()
{
    int a, b, c, d, e, f, k = 0;

    for (a = 1; a <= 6; a++)
        for (b = 1; b <= 6; b++)
            for (c = 1; c <= 6; c++)
                for (d = 1; d <= 6; d++)
                    for (e = 1; e <= 6; e++)
                        for (f = 1; f <= 6; f++)
                            if ((d + b) == (e + c) && (a + d) == (f + c) && (a + e) == (b + f))
                            {
                                k++;
                                printf("      (a=%d)\n",a);
                                printf("     /     \\ \n");
                                printf("  (d=%d)   (e=%d)\n", d, e);
                                printf("   /        \\ \n");
                                printf("(b=%d)-(f=%d)-(c=%d)\n\n", b, f, c);
                                //printf("a=%d,b=%d,c=%d,d=%d,e=%d,f=%d\n",a, b, c, d, e, f);
                            }
    printf("共有: %d 种排列.\n", k);
    return 0;
}