2.3.1 基本数据类型和运算符

　　1 在C语言中，要求运算对象必须是整型的运算符是 % 

　　2 int i = j = 5；→这个定义方法是错的：note: each undeclared identifier is reported only once for each function it appears in。/* int i =5， j = 5；是对的。 */ 

　　3 将整型a，b中较大的数复制给整型c：c =  (a>b)? a : b; √ 

　　4 在C语言中,退格符是 \b :

　　5 int a = 7; float x = 2.5,y = 4.7; 则表达式 x + a % 3 * ( int ) ( x + y ) % 2 / 4 的值是: 2.50000

　　6 int x , i , j ,k; 则x = ( i = 4, j = 16, k = 32 ); x 的值为: 32

1 int main()
2 {
3     int x,j,i,k;
4     x = (i = 4, j = 45 , k = 32);
5     printf("%d",x);
6 return 0;
7     
8     }
9 /*输出结果为32*/

 

　　7 int x = 8, y = 3;问 printf("x = 8,y = 3\n x--:%d ,--y:%d\n",x--,--y); 的输出结果是多少?

 

 int x = 8, y = 3;
    printf("x = 8,y = 3\n x--:%d ,--y:%d\n",x--,--y);
    int a = 8 , b = 3; 
    printf("a = 8,b = 3\n a++:%d,++b:%d\n",a++,++b); 

/*
结果:
x = 8,y = 3
 x--:8 ,--y:2
a = 8,b = 3
 a++:8,++b:4
*/

　　8 设有 int a = 1,b = 2,c = 3, d = 4 ，m = 2,n = 2;则执行语句( m = a > b ) && ( n = c > d );后n的值：

 int a = 1,b = 2,c = 3, d = 4, m = 2,n = 2;
   ( m = a > b ) && ( n = c > d );
   printf("%d",n); 

/*所得结果为2

*/

　　9 已知 int a = 6; ,则执行 a += a- = a*a; 后，a的值为：

    int a = 6;
    a += a -= a*a;
    printf("a的值为：%d\n" , a);

/*
 a的值为： -60
a = 6-6*6
a + = a 

*/

　　10 int x = 1,y = 1 , z = 1; 执行语句 ++x || ++ y && ++z ；后，求表达式 x + y的值：3 

int x = 1, y = 1, z = 1;
    int k = ++x || ++y && ++z;
    printf(" k = ++x || ++y && ++z, k = %d\n", k);
    printf("x = %d\n" , x);
    printf("y = %d\n" , y);
    printf("x+y = %d\n" , x+y);
    
    int j = ++y && ++z; 
    printf(" j = ++y && ++z, j = %d\n", j);
    printf("x = %d\n" , x);
    printf("y = %d\n" , y);
    printf("x+y = %d\n" , x+y);

/*
 k = ++x || ++y && ++z, k = 1
x = 2
y = 1
x+y = 3
 j = ++y && ++z, j = 1
x = 2
y = 2
x+y = 4

*/