采用公式来计算和,效率会快很多
#include<iostream> using namespace std; int sum(int n) { return (1+n)*n/2; } int main(int argc, char* argv[]) { int n; cout<<"请输入n: "; cin>>n; cout<<"1+2+3+4+.....+n-1+n= "<<sum(n)<<endl; return 0; }
采用公式来计算和,效率会快很多
#include<iostream> using namespace std; int sum(int n) { return (1+n)*n/2; } int main(int argc, char* argv[]) { int n; cout<<"请输入n: "; cin>>n; cout<<"1+2+3+4+.....+n-1+n= "<<sum(n)<<endl; return 0; }