一.数组的概念
二.一维数组的使用
cpp
int main()
{
int data[10] = {1,2,3,4,5,6,7,8,9,10};//完全初始化
int data2[10] = { 1,2,3,4,5 };//不完全初始化，剩余的元素默认初始化为0
//int data3[3] = { 1,2,3,4 };//err
int data4[5] = { 1,2,3,4,5 };
int data5[] = { 1,2,3,4,5 };//数组如果初始化了，也可以省略掉数组的小制定，编译器会根据数组的初始化内容
//来确定数组的真实大小
return 0;
}
cpp
int main()
{
int arr[] = { 1,2,3,4,5,6,7,8,9,10 };
// 0 1 2 3 4 5 6 7 8 9
int i = 0;
for (i = 0; i < 10; i++)
{
printf("%d ", arr[i]);
}
//printf("%d\n", arr[6]);
//printf("%d\n", arr[9]);
return 0;
}
cpp
//%p 是打印地址的
int main()
{
int arr[10] = { 0 };
int i = 0;
for (i = 0; i < 10; i++)
{
printf("&arr[%d] = %p\n", i, &arr[i]);//& - 取地址操作符
}
return 0;
}
//
//一维数组在内存中是连续存放的
//随着数组下标的增长，地址是由小到大变化的
//
cpp
int main()
{
//int a = 10;
////sizeof 计算的是变量或者类型的长度，单位是字节
//printf("%d\n", sizeof(a));//4
//printf("%d\n", sizeof(int));//4
int arr[5] = { 0 };
printf("%d\n", sizeof(arr));//40 - 计算的是数组的总大小，单位是字节
printf("%d\n", sizeof(arr[0]));
printf("%d\n", sizeof(arr) / sizeof(arr[0]) );
return 0;
}
cpp
int main()
{
int arr[8] = { 0 };
int i = 0;
int sz = sizeof(arr) / sizeof(arr[0]);
for (i = 0; i < sz; i++)
{
printf("&arr[%d] = %p\n", i, &arr[i]);//& - 取地址操作符
}
return 0;
}三.二维数组
cpp
int main()
{
//int arr[3][5] = {1,2,3,4,5,6,7};//不完全初始化
////依次初始化每一行，当不够的时候，剩余的元素初始化为0
//int arr2[3][5] = { 0 };
//int arr[3][5] = { 1,2,3,4,5, 2,3,4,5,6, 3,4,5,6,7};
//int arr[3][5] = { {1,2},{3,4},{5} };
//二维数组如果初始化，行是可以省略的，但是列不能省略
int arr[][5] = {1,2,3,4,5,6,7};
return 0;
}
cpp
int main()
{
int arr[3][5] = { 1,2,3,4,5, 2,3,4,5,6,3,4,5,6,7 };
printf("%d\n", arr[1][3]);
printf("%d\n", arr[2][4]);
return 0;
}
cpp
int main()
{
int arr[3][5] = { 0 };
//输入数据
int i = 0;//控制行
for (i = 0; i < 3; i++)
{
int j = 0;
//控制的是列
for (j = 0; j < 5; j++)
{
scanf("%d", &arr[i][j]);
printf("%d ", arr[i][j]);
}
}
//输出数组的所有元素
for (i = 0; i < 3; i++)
{
int j = 0;
for (j = 0; j < 5; j++)
{
}
printf("\n");
}
return 0;
}
cpp
int main()
{
int arr[3][5] = { 0 };
//输入数据
int i = 0;//控制行
for (i = 0; i < 3; i++)
{
int j = 0;
//控制的是列
for (j = 0; j < 5; j++)
{
scanf("%d", &arr[i][j]);
printf("%d ", arr[i][j]);
}
}
//输出数组的所有元素
for (i = 0; i < 3; i++)
{
int j = 0;
for (j = 0; j < 5; j++)
{
}
printf("\n");
}
return 0;
}
cpp
int main()
{
int arr[3][5] = { 0 };
int i = 0;
for (i = 0; i < 3; i++)
{
int j = 0;
for (j = 0; j < 5; j++)
{
printf("&arr[%d][%d] = %p\n", i, j, &arr[i][j]);
}
}
return 0;
}
四.C99中的变长数组
cpp
#define M 10
int main()
{
int arr[M];
return 0;
}
五.题目
cpp
#include <string.h>
#include <windows.h>
#include <stdlib.h>
int main()
{
char arr1[] = "welcome to world!!!!!!";
//[welcome to world!!!!!!\0]
// 0
char arr2[] = "####################";
int left = 0;
int right = strlen(arr1)-1;
while (left<=right)
{
arr2[left] = arr1[left];
arr2[right] = arr1[right];
printf("%s\n", arr2);
Sleep(1000);//睡眠1000毫秒
system("cls");//system函数是库函数，执行系统指令，cls是清理控制台屏幕信息
left++;
right--;
}
printf("%s\n", arr2);
return 0;
}strlen:算的是我们对应的数组\0之前的元素(不含\0),sizeof(arr1)/sizeof(arr1[0]):算的是数组的长度
cpp
int main()
{
char arr1[] = "welcome to world!!!!!!";
//[welcome to world!!!!!!\0]
// 0
char arr2[] = "####################";
int left = 0;
//int right = strlen(arr1) - 1;
int sz = sizeof(arr1) / sizeof(arr1[0]);//
int right = sz - 2;
while (left <= right)
{
arr2[left] = arr1[left];
arr2[right] = arr1[right];
printf("%s\n", arr2);
Sleep(1000);//睡眠1000毫秒
system("cls");//system函数是库函数，执行系统指令，cls是清理控制台屏幕信息
left++;
right--;
}
printf("%s\n", arr2);
return 0;
}
cpp
int main()
{
int arr[] = { 1,2,3,4,5,6,7,8,9,10 };//升序的数组
//在数组中查找k - 7
int k = 0;
scanf("%d", &k);
int sz = sizeof(arr) / sizeof(arr[0]);
int i = 0;
for (i = 0; i < sz; i++)
{
if (arr[i] == k)
{
printf("找到了, 下标是%d\n", i);
break;
}
}
if (i == sz)
{
printf("找不到\n");
}
return 0;
}但是遍历的效率太低了
二分查找可以看下面的链接(算法对新手较难):
cpp
int main()
{
int arr[] = { 1,2,3,4,5,6,7,8,9,10 };//升序的数组
//在数组中查找k - 7
int k = 0;
scanf("%d", &k);
int sz = sizeof(arr) / sizeof(arr[0]);
int left = 0;
int right = sz - 1;
while (left<=right)
{
int mid = (left + right) / 2;
if (arr[mid] == k)
{
printf("找到了，下标是:%d\n", mid);
break;
}
else if (arr[mid] < k)
{
left = mid + 1;
}
else
{
right = mid - 1;
}
}
//
if (left > right)
{
printf("找不到\n");
}
return 0;
}方式二.
cpp
int main()
{
int arr[] = { 1,2,3,4,5,6,7,8,9,10 };//升序的数组
//在数组中查找k - 7
int k = 0;
scanf("%d", &k);
int sz = sizeof(arr) / sizeof(arr[0]);
int left = 0;
int right = sz - 1;
int flag = 0;
while (left <= right)
{
int mid = (left + right) / 2;
if (arr[mid] == k)
{
printf("找到了，下标是:%d\n", mid);
flag = 1;
break;
}
else if (arr[mid] < k)
{
left = mid + 1;
}
else
{
right = mid - 1;
}
}
if (flag == 0)
printf("找不到了\n");
return 0;
}