Calculate 1 + 2 + 3 + ...... + 100

1. Use the while statement

 1 using System； 2 class Sum100 3     { 4         static void Main() 5         { 6             int Sum, i; 7             Sum = 0; i = 1; 8             while (i<=100) 9             {10                 Sum += i;11                 i++;12             }13             Console.WriteLine("Sum is" + Sum);14         }15     }

2. Do-while statement

 1 using System; 2 class Sum100 3     { 4         static void Main() 5         { 6             int Sum, i; 7             Sum = 0; i = 1; 8             do  9             {10                 Sum += i;11                 i++;12             }13             while (i<=100)14             Console.WriteLine("Sum is" + Sum);15         }16     }

3. For Statement (1)

 1 using System; 2  3 class Sum100 4     { 5         static void Main() 6         { 7             int Sum, i; 8             Sum = 0; 9             for (i = 1; i <= 100;i++ )10                 Sum += i;11             Console.WriteLine("Sum is" + Sum);12 13             Sum = 0;14             for (i = 100; i > 0;i-- )15                 Sum += i;16             Console.WriteLine("Sum is" + Sum);17         }18     }

4. For Statement (2)

 1 using System; 2  3 class Sum100 4     { 5         static void Main(string[] args) 6         { 7             int Sum, i; 8              9             for (Sum = 0,i = 1; i <= 100;i++ )10                 Sum += i;11             Console.WriteLine("Sum is" + Sum);12 13             14             for (Sum = 0,i <= 100; Sum+i,i++);15                16             Console.WriteLine("Sum is" + Sum);17         }18     }

5. For Statement (3)

 1 using System; 2 class Sum100 3     { 4         static void Main(string[] args) 5         { 6             int Sum, i; 7  8             for (Sum = 0, i = 1; i <= 100; ) 9                 Sum += i++;10             Console.WriteLine("Sum is" + Sum);11 12             13             for (Sum = 0,i =1; ;Sum+=i,i++)14                if(i>100)  break;15             Console.WriteLine("Sum is" + Sum);16 17             Sum=0;i=1;18             for(;;)19             {20                 Sum+=i++;21                 if (i>100)22                     break;23             }24             Console.WriteLine("Sum is" + Sum);25         }26     }

 

Calculate 1 + 2 + 3 + ...... + 100