檸檬的C語言初學日誌

輸入6，印出1-2+3-6之和
測資:
輸入6
印出-4
輸入12
印出-8

//解題思路: 先找到6的因數，再將因數做加減 第偶數個因數用減的 第奇數個因數用加的
#include <iostream>

using namespace std;

int main()
{
    while(1){
        int i=0,x,j,element,sum=0;
        cin >> x;
        for(j=1;j<=x;j++){
            if(x%j==0){
                element=j;
                i++;
                if(i%2==0){
                    sum=sum-element;
                }
                if(i%2!=0){
                    sum=sum+element;
                }
            }
        }
        cout << sum << endl;
    }
    return 0;
}

#include <iostream>
#include <cstdlib>
using namespace std;

int main()
{
    //定義一個整數變數
    int inum;
    int refer;
    while(1){
       //輸入一個整數值
       cout << "請輸入一個整數值: ";
       cin >> inum;
       for( refer = 2 ; refer <= inum ; refer++ ){
          if(refer == inum) cout << "此數是質數" << endl;
          else if(inum % refer == 0) {
                cout << "此數不是質數" << endl;
                break;
          }
          else {
               continue;
               cout << "此數是質數" << endl;
          }
       }
    }
    return 0;
    system("pause");
}

使用for迴圈
#include <iostream>
#include <cstdlib>
using namespace std;

int main()
{
    //定義一個整數變數
    int i = 1 , j = 1 , product = 1;

    for( i = 1 ; i < 10 ; i++){
        //i * j = product
        for( j = 1 ; j < 10 ; j++){
         product = i * j ;
         cout << " " << i;
         cout << "*" << j ;
         //如果 product < 10 則多加1個空格!!!
         if( product < 10 ) cout << "= " << product ;
         else cout << "=" << product ;
        }
        cout << endl;
    }
    return 0;
    system("pause");
}

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使用do-while迴圈(包一個for迴圈)

使用for迴圈
#include <iostream>
#include <cstdlib>
using namespace std;

int main()
{
    //定義一個整數變數
    int inum , cube , sum = 0;

    for( inum = 1 ; inum < 101 ; inum++ ){
        cube = inum * inum * inum;
        sum = sum + cube;
    }
    //輸出1~100立方值的總和 //end1是換行
    cout << "1~100立方值的總和是: " << sum << endl;
    return 0;
    system("pause");
}

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使用while迴圈