练习-循环控制训练等你来挑战!!!

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循环练习第1关

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难度: 1

行数和每行*的个数，由用户输入。
参考:

#include <iostream>

using namespace std;

int main() {
	int row = 0;
	int list = 0;

	cout<<"Please enter the line you want to enter: ";
	cin>>row;
	cout<<"Please enter the column you want to enter: ";
	cin>>list;
	
	for (int i = 1; i <= row; i++) {
		for (int j = 1; j <= list; j++) {
			cout<<"*";
		}
		cout<<endl;
	}

	return 0;
}

循环练习第2关

难度 1.5

参考:

#include <iostream>

using namespace std;

int main() {
	int row = 0;

	cout<<"Please enter the number of rows: ";
	cin>>row;

	for (int i = 0; i < row; i++) {
		for (int j = 0; j < i+1; j++) {
			cout<<"*";
		}
		cout<<endl;
	}

	return 0;
}

循环练习第3关

难度: 1.5

参考:

#include <iostream>

using namespace std;

int main() {
	int row = 0;

	cout<<"Please enter the number of rows: ";
	cin>>row;

	for (int i = 0; i < row; i++) {
		for(int j = 0; j < row - i; j++) {
			cout<<"*";
		}
		cout<<endl;
	}

  	return 0;
}

循环练习第4关

难度系数2.0

参考:

#include <iostream>

using namespace std;

int main() {
	int rows;

	cout<<"Please enter the number of rows: ";
	cin>>rows;

	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < rows - i - 1; j++) {
			cout<<" ";
		}
		for (int k = 0; k < i * 2 + 1; k++) {
			cout<<"*";
		}
		cout<<endl;
	}

	return 0;
}

循环练习第5关

难度:2.5
打印乘法口诀表

参考:

#include <iostream>

using namespace std;

int main() {
	
	for (int i = 1; i <= 9; i++) {
		for(int j = 1; j <= 9; j++) {
			if (j <= i) {
				cout<<j<<"*"<<i<<"="<<i*j<<"	";
			}
		}
		cout<<endl;
	}

	return 0;
}

循环练习第6关

输出所有水仙花数
水仙花数: 3位数字, 各位的立方之和,等于这个数本身.
说明: 严格的说只有3位的整数, 才可能是水仙花数

参考:

#include <iostream>
#include <iomanip>

using namespace std;

int main() {
	int a, b, c = 0;

	for (int i = 100; i <= 999; i++) {
		a = i % 10;
		b = (i / 10) % 10;
		c = i / 100;

		if (a * a * a + b * b * b + c * c * c == i) {
			cout<<i<<endl;
		}
	}

	return 0;
}

**

循环练习第7关

**
输出指定项的斐波那契数列.
1, 1, 2, 3, 5, 8, 13, 21, …
难度: 2.5

参考:

#include <iostream>
#include <iomanip>
#include <unistd.h>

using namespace std;

int main() {
	int n = 0;
	long long a = 1;
	long long b = 1;
	long long value;

	cout<<"Please enter the number of Fibonacci Numbers: ";
	cin>>n;

	if (n <= 0) {
		cout<<"We want a positive integer greater than zero."<<endl;
		sleep(2);
		return 1;
	}

	if (n == 1) {
		cout<<"1"<<endl;
		sleep(2);
		return 0;
	}

	if (n == 2) {
		cout<<"1 1"<<endl;
		sleep(2);
		return 0;
	}

	cout<<"1 1 ";
	for (int i = 3; i <=n; i++) {
		value = a + b;
		a = b;
		b = value;
		cout<<value<<" ";
	}

	cout<<endl;

	return 0;
}

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循环练习第8关

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输入一个10进制的正整数，把它转换为2进制输出。
6
110

参考:

#include <iostream>
#include <iomanip>
#include <unistd.h>

using namespace std;

int main() {
	int ret[32] = {0};
	int n;
	int i;

	cout<<"Please enter a positive integer: ";
	cin>>n;

	if (n < 0){
		cout<<"Please enter a positive integer!!!"<<endl;
		sleep(2);
		return 1;
	}

	i = 0;
	while (n != 0) {
		ret[i] = n % 2;
		n = n/2;
		i++;
	}

	for (i--; i >= 0; i--) {
		cout<<ret[i];
	}
	cout<<endl;

	return 0;
}

循环练习第9关

输入一个2进制正数，把它转换为10进制输出。

参考:

#include <iostream>
#include <string>

using namespace std;

int main() {
	string str;
	int s = 0;
	int p = 1;

	cout<<"Please enter a binary number: ";
	cin>>str;

	for (int i = str.length() - 1; i >= 0; i--) {
		int x = str[i] - '0';
		s += x*p;
		p = p * 2;
	}

	cout<<"s="<<s<<endl;
	
	return 0;
}

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循环练习第10关

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输入一个字符串，然后把这个字符串逆转输出
123456789
987654321

参考:

#include <iostream>
#include <string>

using namespace std;

int main() {
	string str;
	int i;
	int j;
	char tmp;

	cout<<"Please enter a string: "<<endl;
	cin>>str;

	i = 0;
	j = str.length() - 1;
	while (i < j) {
		tmp = str[i];
		str[i] = str[j];
		str[j] = tmp;
		i++;
		j--;
	}
	
	cout<<str<<endl;
	
	return 0;
}