練習題

1. 水仙花數

   水仙花數是指三位數，這三位數滿足：個位2 + 十位2 + 百位**2 = 這個三位數本身。

   #include<stdio.h>
   
   int main()
   {
   	int num = 100;
   	int the_uint, the_decade, the_hundred;
   	for(num; num<1000; num++)
   	{	
   		the_hundred = num/100;
   		the_decade = (num - the_hundred * 100)/10;
   		the_uint = num%10;
   		if(the_uint*the_uint + the_decade*the_decade + the_hundred*the_hundred == num)
   		{
   			printf("水仙花數：%d\n", num);
   		}
   	}
   	return 0;
   }
    
   

2. 99乘法表

   #include<stdio.h>
   
   int main()
   {
   	int mul1, mul2;
   	for(mul1=1; mul1<10; mul1++)
   	{
   		for(mul2=1; mul2<=mul1; mul2++)
   		{
   			printf("%d*%d=%d\t", mul1, mul2, mul1*mul2);
   		}
   		printf("\n");
   	}
   	return 0;
   }