58_3_29 上课笔记

int Add(int x,int )
{
int z=x+y;
return z;
}
● x,y称为形式参数，也是输入参数
● 返回值 int表示返回整型
void表示无返回值
● 函数体命名尽量见名知意
● Add(x,y),x,y为实际参数
● 函数体:自创函数的核心部分

● sz = sizeof(arr1) / sizeof(arr1[0]);
● 前者为整个数组的大小
● 后者为一个元素的大小
● 数组未初始化会输出随机值
● 数组是通过下标来访问的

● >>右移一位
● <<左移一位
● &，|，^
[图片]
[图片]
● 定义变量
● int a=10;

1. 内存大小由数据类型决定
2. 向内存里放置数据(赋值或初始化)

● typedef:类型重命名

1. typedef 原类型名 修改后的类型名

[图片]

[图片]
//#include <stdio.h>
//#include <stdlib.h>
//#include <string.h>
//#include <windows.h>
//
//
/Kpedef unsigned long long ull_t;
//类型重命名

//int ADD(int _x,int _y)
//{
// int _z = _x + _y;
// return _z;
//}
//int DIV(int _x, int _y)
//{
// if (0 == _y)
// {
// printf(“DIV zero!!!\nERROR\n”);
// return - 1;
// }
// int _z = _x / _y;
// return _z;
//}
//int main()
//{
/ar arr1[] = “bit”;
/ar arr2[] = { ‘b’,‘i’,‘t’ };
/ar arr3[] = { ‘b’,‘i’,‘t’,’\0’ };
//printf(“arr1==%s\n”, arr1);
//printf(“arr2==%s\n”, arr2);
//printf(“arr3==%s\n”, arr3);
//printf(“arr1长度==%d\n”, strlen(arr1));
//printf(“arr2长度==%d\n”, strlen(arr2));//没有\0随机值
//printf(“arr3长度==%d\n”, strlen(arr3));

//int coding = 0;
//printf("你会去敲代码吗？（1 Or 0）：-->");
//scanf("%d", &coding);
//if (coding == 1)
//{
//	printf("大牛");
//}
//else
//{
//	*/printf("菜鸟");
//}

//int x = 0;
//int y = 0;
//printf("请输入你的数据<x,y>:-->");
//scanf("%d %d", &x, &y);
//int ret = x + y;
//printf("%d+%d=%d\n",x,y, ret);

//int x = 0;
//int y = 0;
//printf("请输入你的数据<x,y>:-->");
//scanf("%d %d", &x, &y);
//int ret = ADD(x, y);
//printf("%d+%d=%d\n", x, y, ret);

//int x = 0;
//int y = 0;
//printf("请输入你的数据<x,y>:-->");
//scanf("%d %d", &x, &y);
//int ret = DIV(x, y);
//printf("%d/%d=%d\n", x, y, ret);

//int arr1[] = { 1,2,3,4,5,6,7,8,9,10 };
/ar arr2[] = {'a'};
//double arr3[] = { 2.34 };
//int i = 0;
//int sum = 0;
//int sz = sizeof(arr1) / sizeof(arr1[0]);
////整个数组的大小除以一个元素的大小
//for (i = 0; i < sz; i++)
//{
//	sum += arr1[i];
//	printf("arr1[%d] = %d\n",i, arr1[i]);
//}
//printf("数组内数字之和为%d\n",sum);

//int x = 15;//1000 100 10 1-->00000000 00000000 00000000 0000 1111
//printf("%d右移一位%d\n",x,x >> 1);//右移一位
//printf("%d左移一位%d\n",x,x << 1);//左移一位
//printf("%d\n",x);
//int x = 1;
//printf("%d ", x << 1);//2
//printf("%d ", x << 2);//4
//printf("%d ", x << 3);//8
//printf("%d ", x << 4);//16
//printf("%d ", x << 5);//32

//printf("%d\n", 1 & 1);
//printf("%d\n", 1 & 0);
//printf("%d\n", 0 & 0);
//printf("%d\n", 0 & 1);
//printf("%d\n", 2 & 6);
//puts(" ");
//printf("%d\n", 1 | 1);
//printf("%d\n", 1 | 0);
//printf("%d\n", 0 | 1);
//printf("%d\n", 0 | 0);
//printf("%d\n", 2 | 6);
//puts(" ");
//printf("%d\n", 1 ^ 1);
//printf("%d\n", 1 ^ 0);
//printf("%d\n", 0 ^ 1);
//printf("%d\n", 0 ^ 0);
//printf("%d\n", 2 ^ 6);

//int flag = 1;
////if (!(1 == flag))//!逻辑取反
//if(1==flag)
//{
//	printf("CCCCCCC\n");
//}
//else
//{
//	printf("BBBBBBBBBBBB\n");
//}

//int x = 10;
//printf("%d\n", x);
//printf("0x%p\n",&x);

//unsigned int x = 1;
//printf("%u\n", ~x);

//int x = 10;
//int y = 20;
//if (x > y)
//{
//	printf("X>Y");
//}
//else if (y > x)
//{
//	printf("y>x");
//}
//else
//{
//	printf("x=y");
//}

//int x = 10;
//int y = 20;
//if (x > 10 && y <= 20)
//{
//	printf("AAAAAAAAAAAAAAAAAAAA\n");
//}
//else
//{
//	printf("aaaaaaaaaa\n");
//}
//puts("");
//if (x > 10 || y <= 20)
//{
//	printf("AAAAAAAAAAAAAAAAAAAA\n");
//}
//else
//{
//	printf("aaaaaaaaaa\n");
//}

//printf("请输入两个数<x,y>:-->");
//int x = 0;
//int y = 0;
//scanf("%d %d", &x, &y);
//int max = 0;
//max = x > y ? x : y;
//printf("max=%d", max);
//if (x > y)
//{
//	max = x;
//}
//else
//{
//	max = y;
//}
//printf("max=%d", max);

/ar arr[] = {'b','i','t'};
//printf("%s\n", arr);
//printf("%d\n", sizeof(arr));
//printf("%d\n", strlen(arr));
//printf("%d\n%d\n", sizeof(arr), strlen(arr));

//unsigned long long x = 1000000;
//unsigned long long y = 98000000;
//ull_t z = 8763200;
//ull_t a = 8283472453;
//printf("%lld %lld %lld %lld\n", x, y, z, a);
//return 0;

//}