The order of for statements
for (initial expression ① ; conditional expression ② ; end loop ④ )
{ ③ // ①②③④ representing a sequence program running } initial expression ① data structure can be created directly, i.e.: int i = 0;
Knock on the table
Rule : Among 1-100 numbers, the ones digit has 7, the tens digit has 7, and the multiples of 7 are printed and knocked on the table, and the rest are printed directly
#include <iostream>
using namespace std;
int main()
{
/*for(起始表达式①;条件表达式②;末尾循环体④)
{
③ //①②③④代表程序运行的顺序
}
*起始表达式①可以直接创建数据结构，即：int i = 0;
*/
//敲桌子程序
//1-100个数里面，个位有7，十位有7，7的倍数就打印敲桌子，其余的直接打印
for (int i = 1; i <= 100; i++)
{
if (i % 7 == 0 || i % 10 == 7 || i / 10 == 7)
{
cout << "敲桌子" << endl;
}
else
cout << i << endl;
}
return 0;
}
/* 嵌套循环：
*在一个循环里面不能重复使用一个字母
* 程序选择具有就近原则
* 内层运行完后，外层一次
* 外层一次，内层一周，内部全部完成才可以运行外层
*/
Nested loop :
- One letter cannot be reused in a cycle
- Procedure selection has the principle of proximity
- After the inner layer runs, the outer layer once
- The outer layer is once, the inner layer is one week, and the inner layer is completely completed before the outer layer can be operated.
Multiplication formula table
#include <iostream>
using namespace std;
int main()
{
/*乘法口诀表
分析：
* i为行，j为列
* 当 列j > 行i 时候，不继续打印
* i * j = i*j;
*/
for (int i = 1; i <= 9; i++)
{
for (int j = 1; j <= i; j++)
{
cout << i << " * " << j <<" = " << i * j << " ";
}
cout << endl;
}
return 0;
}
break use
Used to select or loop structure
- ① switch, terminate the case statement, jump out of switch
- ② Cycle: Jump out of the current cycle
- ③ Nesting: Jump out of the nearest inner loop
#include <iostream>
using namespace std;
int main()
{
/*break用于选择或者循环结构
* ① switch，终止 case 语句，跳出 switch
* ② 循环 : 跳出当前循环
* ③ 嵌套 : 跳出最近的内层循环
*/
//①.[switch ：终止 case 语句，跳出 switch]链接：
//(https://blog.csdn.net/weixin_42198265/article/details/113408616)
//②. 循环 : 跳出当前循环
int score = 0;
while (score <= 10)
{
score++;
cout << score << endl;
if (score >= 5)
break;
}
//③ 嵌套 : 跳出最近的内层循环
for (int i = 1; i <= 5; i++)
{
for (int j = 1; j <= i; j++)
{
cout << j;
if (j >= 3)
break;
}
cout << endl;
}
return 0;
}
continue : In the loop, only skip the unfinished part of the loop
#include <iostream>
using namespace std;
int main()
{
//continue : 在循环中，仅仅跳本次循环未循环完的部分
//例子 : 1-100中只输出偶数，不输出奇数
for (int i = 1; i <= 100; i++)
{
if (i % 2 == 0)
cout << i << endl;
else
continue;
}
return 0;
}
The goto statement uses:
goto mark;
…
mark:
#include <iostream>
using namespace std;
int main()
{
/*goto语句
* 使用方法：
*
* goto标记；
* 标记：
*/
cout << "1" << endl;
cout << "2" << endl;
goto end;
cout << "3" << endl;
cout << "4" << endl;
end: //3和4不被=
cout << "5" << endl;
cout << "6" << endl;
return 0;
}