# The sword refers to the offer series source code-beg 1+2+3+...+n

Source: Internet
Author: User

`Topic 1506: Seeking 1+2+3+...+n time limit: 1 seconds Memory limit: 128 Mega Special: No submission: 1260 Resolution: 722 Title Description: Ask for 1+2+3+...+n, cannot use multiplication method, for, while, if, else, switch, Case keyword and conditional judgment statement (A? B:C). Input: The input may contain multiple test samples. For each test case, the input is an integer n (1<= n<=100000). Output: Corresponds to each test case and outputs the value of the 1+2+3+...+n. Sample input: 35 Sample output: 615`

Solution one: Using a construction method to simulate loops

`#include <iostream> #include <stdio.h>using namespace Std;class temp{public:    Temp () {        n++;        sum+=n;    }    static void Reset () {        n=0;        sum=0;    }    static unsigned int getsum () {        return Sum;    } Private:    static unsigned int N;    static unsigned int Sum;}; unsigned int temp::n = 0;unsigned int temp::sum = 0;unsigned int Sum (int N) {    temp::reset ();    Temp::reset ();    Temp*a = new Temp[n];    Delete[] A;    A = NULL;    return Temp::getsum ();} int main () {   int n;   while (scanf ("%d", &n)!=eof) {    printf ("%d\n", SUM (n));   }    return 0;}`

The sword refers to the offer series source code-beg 1+2+3+...+n

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