#include <stdio.h>
int main()
{
??? /* 小伙伴們：
?????????? 選擇你們認為最合理的循環結構完成功能吧 */
??? int sum = 0;? //定義計算結果變量sum
??? int i = 1;??? //定義循環數字變量i
??? int flag = 1; //定義符號狀態變量flag
???
??? //使用while循環
??? while(i<=100)
??? {
??????? i=i*flag;
??????? flag=-flag;
??????? i++;
??????? sum=sum+i;
??? }
???
??? i = 1;? //重新初始化變量i
???
??? //do-while循環
??? do{
??????? i=i*flag;
??????? flag=-flag;
??????? i++;
??????? sum=sum+i;
??? }while(i<=100);
???
??? i = 1;? //重新初始化變量i
???
??? //使用for循環
??? for(i=1;i<=100;i++)
??? {
??????? i=i*flag;
??????? flag=-flag;
??????? sum=sum+i;
??? }?
??? printf("sum=%d\n",sum);
???
??? return 0;???
}