C++求1到10这10个数之和

#include<iostream>
int main()
{
    int sum=0,val=1;
    while(val<=10){
        sum+=val;
        ++val;
    }
    std::cout<<"1到10之和是"
            <<sum<<std::endl;
    return 0;
}

#include<iostream>
int main()
{
    int sum=0;
    for(int val=1;val<=10;++val)
        sum+=val;
    std::cout<<"1到10之和是"
            <<sum<<std:endl;
    return 0;
}