随机一个个位数，然后把个位数strcat到字符串尾部//不知道为什么正确的怎么做？
char numi[8] = {};
char numr[8] = {};
char c[2] = {};
cin>>numi;
srand((unsigned)time(NULL));
for(int i = 0; i< 7;i++)
{
int nRnd = rand();
strcat(numr,itoa(nRnd,c,10));
memset(c,2,0);
}
[解决办法]
int nRnd = rand() % 10; // 保证你的随机数 nRnd 是个位数。
int rand (void);
Returns a pseudo-random integral number in the range between 0 and RAND_MAX.
RAND_MAX
This value is library-dependent, but is guaranteed to be at least 32767
