Question

急求：c#编程题的答案：求表达式的值:1+1/2-1/3+1/4-1/5+1/6-..........+1/20

需要程序的代码，谢谢了

Answer 1

int sum=1;
int tmp=0;
for (int i = 1; i <= 20; i++)
{
Math.DivRem(i, 2,out tmp) ;
if (i!=1 &&tmp == 0)
{
sum -= 1 / (i + 1);
}
else
{
sum += 1 / (i + 1);
}

}

Answer 2

float sum = 1;
bool b=true;
for (int i = 2; i <= 20; i++)
{
if (b)
{ sum += (float)1 / i; b = false; }
else
{ sum -= (float)1 / i; b = true; }
}
Console.Write(sum);

Answer 3

float sum=1;
for (int i =1; i < 20;i++ )
{
if (i % 2 == 0)
{
sum -= i / (i + 1);
}
else {
sum += i / (i + 1);
}
}

Answer 4

bool bol = true;
double b =1 ;
for (int a = 2; a <= 20; a++)
{
if (bol)
{
b = b + 1.0 / a ;
bol = false;
}
else
{
b = b - 1.0 / a ;
bol = true;
}
}

Answer 5

float count=0;
for(int i=1;i<=20;i++)
{
float index=1/i;
if(i!=1&&i%2==1)
{
index=-index;
}
count+=index;
}

输出count