九九乘法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[,] d = new int[10, 10];
            int sum = 0;
            for (int i = 1; i <= 9; i++)
                for (int j = 1; j <= 9; j++)
                {
                    sum = i * j;
                }
            for (int i = 1; i <= 9; i++)
                for (int j = 1; j <= 9; j++)
                {
                    sum = i * j;
                    Console.WriteLine(i + "*" + j + "=" + sum);
                }
        }
    }
}

1+2+...+100

#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
  int i;
  int sum=0;
    for( i = 1 ; i <= 100 ; ++i )
       {
           sum+=i;
           }
       printf("%d\n",sum);

  system("PAUSE");
  return 0;
}