望采纳!!!
1.用for语句实现
#include<iostream>
using namespace std;
int main()
{
int i, sum = 0,n;
cin >> n;
for (i = 1; i <= n; i++)
{
sum = sum + i;
}
cout << sum << endl;
return 0;
}
2.用while语句实现
#include <iostream>
using namespace std;
int main()
{
int i=1, sum = 0,n;
cout << "请输入最大数字:" << endl;
cin >> n;
while (i <= n)
{
sum = sum + i;
i++;
}
cout << sum << endl;
return 0;
}
3.用do-while语句实现
#include <iostream>
using namespace std;
int main()
{
int i=1, n, sum = 0;
cout << "请输入最大数字" << endl;
cin >> n;
do {
sum = sum + i;
i++;
} while (i <= n);
cout << sum << endl;
return 0;
}