请用C语言标注一下注释

#include<stdlib.h>//常用系统函数调用
#include<stdio.h>
#include<time.h>
int main()

{

int answer;
 srand((unsigned)time(NULL));
int a=rand();
int b=rand();
a=rand()%10+1;
b=rand()%10+1;
do{
printf("%d*%d=?\n",a,b);
scanf("%d",&answer);
if(answer==a*b)
{
    printf("Right!");
}
else
{
    printf("Wrong! please try again!");
    printf("\n");
}
}while(answer!=a*b);
return 0;

}

int answer;
 srand((unsigned)time(NULL));   //随机数种子
int a=rand();      //产生两个随机数，这两行都是废代码
int b=rand();
a=rand()%10+1;   //产生1-10之间的整数
b=rand()%10+1;
do{
printf("%d*%d=?\n",a,b);  //显示乘法计算式
scanf("%d",&answer);  //让用户输入乘法结果
if(answer==a*b)  //判断结果正确，输出Right
{
    printf("Right!");
}
else
{
    printf("Wrong! please try again!");  //不正确提示
    printf("\n");
}
}while(answer!=a*b);   //不正确则继续让用户输入
return 0;