int main()
{
//打印10*10正方形点阵
for (int i = 0; i < 10; i++)
{
for (int i = 0; i < 10; i++)
{
cout << "*";
}
cout << endl;
}
return 0;
}
1. 选择结构 1)if语句
实例:
//多条if语句形式
int main()
{
int pig1 = 0;
int pig2 = 0;
int pig3 = 0;
int max = 0;
cout << "请输入三只小猪的体重:" << endl;
cout << "pig1:" << endl;
cin >> pig1;
cout << "pig2:" << endl;
cin >> pig2;
cout << "pig3:" << endl;
cin >> pig3;
if (pig1 >= pig2 && pig1 >= pig3)
{
cout << "体重最重的小猪是小猪1" << endl;
}
else if (pig1 >= pig2 && pig1<= pig3)
{
cout << "体重最重的小猪是小猪3" << endl;
}
else if (pig1 <= pig2 && pig2 <= pig3)
{
cout << "体重最重的小猪是小猪3" << endl;
}
else if (pig1 <= pig2 && pig2 >= pig3)
{
cout << "体重最重的小猪是小猪2" << endl;
}
return 0;
}
//嵌套if语句形式
int main()
{
int pig1 = 0;
int pig2 = 0;
int pig3 = 0;
int max = 0;
cout << "请输入三只小猪的体重:" << endl;
cout << "pig1:" << endl;
cin >> pig1;
cout << "pig2:" << endl;
cin >> pig2;
cout << "pig3:" << endl;
cin >> pig3;
if (pig1 > pig2)
{
if (pig1 > pig3)
{
cout << "小猪1最重" << endl;
}
else
{
cout << "小猪3最重" << endl;
}
}
else
{
if (pig2 > pig3)
{
cout << "小猪2最重" << endl;
}
else
{
cout << "小猪3最重" << endl;
}
}
return 0;
}
2)三目运算符
3)switch语句
//switch语句只能判断整型或者字符型,不能对区间进行判定
int main()
{
int score = 0;
cout << "请输入您的评分:" << endl;
cin >> score;
switch (score)
{
case 5:
cout << "您对电影的评级为优秀" << endl;
break;
case 4:
cout << "您对电影的评级为良好" << endl;
break;
case 3:
cout << "您对电影的评级为不错" << endl;
break;
case 2:
cout << "您对电影的评级为还行" << endl;
break;
case 1:
cout << "您对电影的评级为烂片" << endl;
break;
}
return 0;
}
2. 循环结构
1)while循环语句
int main()
{
int RandNumber = rand() % 100 + 1;//生成一个1到100之间的随机数
cout << "系统给出的随机数字是:" << RandNumber << endl;
int GuessNumber = 0;
cout << "请输入您猜想的数字:" << endl;
cin >> GuessNumber;
while (GuessNumber != RandNumber)
{
if (GuessNumber > RandNumber)
{
cout << "抱歉,您猜测的数字过大。请继续!" << endl;
cout << "请输入您猜想的数字:" << endl;
}
else
{
cout << "抱歉,您猜测的数字过小。请继续!" << endl;
cout << "请输入您猜想的数字:" << endl;
}
cin >> GuessNumber;
}
cout << "恭喜,您猜对了。" << endl;
return 0;
}
2)do...while循环语句
int main()
{
//输出0-9之间的数字
int num = 0;
do
{
cout << num << endl;
num++;
} while (num < 10);
return 0;
}
int main()
{
//输出所有的水仙花数
int num = 100;
int num100 = 0;
int num10 = 0;
int num1 = 0;
do
{
num100 = num / 100;
num10 = (num - num100*100)/10;
num1 = num % 10;
if (num == pow(num100,3) + pow(num10, 3) + pow(num1, 3))
{
cout << num << endl;
}
num++;
} while (num < 1000);
return 0;
}
3)for循环语句
int main()
{
//敲桌子问题
for (int num = 1; num <= 100; num++)
{
if (num % 10 == 7)
{
cout << "敲桌子" << endl;
}
else if (num / 10 == 7)
{
cout << "敲桌子" << endl;
}
else if (num % 7 == 0)
{
cout << "敲桌子" << endl;
}
else
{
cout << num << endl;
}
}
return 0;
}
4)嵌套循环
int main()
{
//打印九九乘法口诀表
for (int i = 1; i < 10; i++)
{
for (int j = 1; j <= i; j++)
{
cout << j << "x" << i << "=" << i * j << " ";
}
cout << endl;
}
return 0;
}
3. 跳转语句 1)break语句 2)continue语句
在循环语句中,跳过本次循环中余下尚未执行的语句,继续执行下一次循环
3)goto语句



