int i,sum;sum=0;for(i=0;i<49;i++)}class hepublic static void main(String[] args)int number = 1; //初始值1,以后再+2递增上去int sum = 0;for ( ; number <100; number+=2 )System.out.println(“1+3+5+7+……+99= ” +sum);}}private sub form_click() dim sum as integer, i as integer sum = 0 for i = 1 to 99 step 2 sum = sum + i next i msgbox "1+3+5+…+99=" & sum, end sub
都是c语言,我用c#回答吧。using System;using System.Collections.Generic;using System.Text;namespace __3_7 class Program static void Main(string[] args) int[] x = new int[50]; int sum = 0; for (int n = 1; n <= 50; n++) x[n - 1] = 2 * n - 1; if((n-1)%2==0) sum=sum+x[n-1]; } else sum=sum-x[n-1]; } } Console.WriteLine(sum); } }}main()int result=0;int i;int n=1;for(i=1;i<=99;i=i+2)i=i*n;result+=i;n=-n;}printf("%d",result);}#include <stdio.h>void main() int sum = 0; bool b = true; for (int i = 1; i<= 99; i +=2) if (b) sum += i; else sum -=i; b = !b; } printf("%d", sum); getchar();}结果是-50#include <stdio.h>void main()int sum = 0;int flag = 1;int i = 0;for (i = 0; i < 50; i++)sum += flag * (2 * i + 1);flag = -flag;}printf("the result is %d", sum);}#include <stdio.h>void main(void) for(i=1;i<100;i+=2) sign=-sign; } printf("sum=%d\n",sum);}