C++ 程序查找自然数之和

编写一个C++程序来查找从1到n的自然数之和。此程序允许您输入最大数字来计算自然数之和。接下来，我们使用while循环通过递增i值来迭代从1到n。在循环中，我们将i的每个值加到sum中并打印sum。

#include<iostream>

using namespace std;

int main()
{
	int number, i = 1, sum = 0;
	
	cout << "\nPlease Enter the Number to find Sum of Natural Num  =  ";
	cin >> number;
	
	while( i <= number)
	{
		sum = sum + i;
		i++;
	}
			
	cout << "\nThe Sum of Natural Number from 1 to " << number << " = " << sum;

 	return 0;
}

Please Enter the Number to find Sum of Natural Num  =  10

The Sum of Natural Number from 1 to 10 = 55

下面的程序显示了使用Do While循环的自然数之和示例代码。

#include<iostream>

using namespace std;

int main()
{
	int number, i = 1, sum = 0;
	
	cout << "\nPlease Enter the Number to find Sum of Natural Num  =  ";
	cin >> number;
	
	do
	{
		sum = sum + i;
		i++;		
	} while( i <= number);
			
	cout << "\nThe Sum of Natural Number from 1 to " << number << " = " << sum;

 	return 0;
}

Please Enter the Number to find Sum of Natural Num  =  20

The Sum of Natural Number from 1 to 20 = 210

C++ 程序使用 For 循环查找自然数之和

在这里，我们在for循环中添加了一个额外的cout语句：cout << “\n Iteration = ” << i << “, i = ” << i << “, sum = “<< sum << ” + ” << i << ” = “<< sum + i;。此语句可帮助您逐次理解程序。

#include<iostream>

using namespace std;

int main()
{
	int number, i = 1, sum = 0;
	
	cout << "\nPlease Enter the Number to find Sum of Natural Num  =  ";
	cin >> number;
	
	for(i = 1; i <= number; i++)
	{
		cout << "\n Iteration = " << i << ", i = " << i << ", sum = "<< sum << " + " << i << " = "<< sum + i;
		sum = sum + i;
		
	}
			
	cout << "\nThe Sum of Natural Number from 1 to " << number << " = " << sum;

 	return 0;
}

这个程序有助于使用函数计算自然数之和。

#include<iostream>

using namespace std;

int sumOfNaturalNumbers(int number)
{
	int sum = 0;
	
	for(int i = 1; i <= number; i++)
	{
		sum = sum + i;
		
	}
	return sum;
}
int main()
{
	int number;
	
	cout << "\nPlease Enter the Number to find Sum of Natural Num  =  ";
	cin >> number;
	
	int sum = sumOfNaturalNumbers(number);
			
	cout << "\nThe Sum of Natural Number from 1 to " << number << " = " << sum;

 	return 0;
}

Please Enter the Number to find Sum of Natural Num  =  25

The Sum of Natural Number from 1 to 25 = 325

使用数学公式计算自然数之和

众所周知，计算自然数之和的数学公式为=数字 * (数字 + 1) / 2)。

#include<iostream>

using namespace std;

int sumOfNaturalNumbers(int number)
{
	
	if(number == 0)
	{
		return number;
	}
	else
	{
		return (number * (number + 1) / 2);
	}
}
int main()
{
	int number;
	
	cout << "\nPlease Enter the Number  =  ";
	cin >> number;
	
	int sum = sumOfNaturalNumbers(number);
			
	cout << "\nThe Sum of Natural Number from 1 to " << number << " = " << sum;

 	return 0;
}

Please Enter the Number  =  50

The Sum of Natural Number from 1 to 50 = 1275

下面的程序将使用递归计算自然数之和。

#include<iostream>

using namespace std;

int sumOfNaturalNumbers(int number)
{
	
	if(number == 0)
	{
		return number;
	}
	else
	{
		return (number + sumOfNaturalNumbers(number - 1));
	}
}
int main()
{
	int number;
	
	cout << "\nPlease Enter the Number  =  ";
	cin >> number;
	
	int sum = sumOfNaturalNumbers(number);
			
	cout << "\nThe Sum of Natural Number from 1 to " << number << " = " << sum;

 	return 0;
}

Please Enter the Number  =  90

The Sum of Natural Number from 1 to 90 = 4095