1.

# include < stdio . h >void main ()
{int x , i ;for ( i =1; i <=100; i ++)
{X = i ;if (++ x %2==0)if (++ x %3==0)if (++ x %7==0)printf ("% d ", x );
}}

答案：28  70 

2.

# include < stdio . h >int main ()
{ int a [3][3]=((1,2,3),(4,6,2),(9,3,6}), s =0;int i , j , k =1;for ( i =0; i <3; i ++)
{for ( j =0; j <3: j ++)a [ il [ j ]= a [ i ][ j ]/ k ;k ++;
}for ( i =0; i <3; i ++)s += a [ i ] [i ];printf ("% d ", s );return 0;
}

答案：6

3.

# include < stdio . h >union myun 
{ struct 
{ int x , y , z ;}u ;int k ;}a ；void main （)
{a . u . x =4; a . u . y =5; a . u . z =6; a . k =0;printf ("% d \ n ", a . u . x );
}

答案：0