C语言应用递归调用的方法分别求1+2+3.......+100或N!

/// <summary>
/// 计算小于某整数的加法、乘法
/// </summary>
/// <param name="Ctype">为真是加，假为乘</param>
/// <param name="endNum">最大数</param>
/// <returns>返回值</returns>
public double compute(bool Ctype, int endNum)
{
double tempNum = 0;

if (endNum-1 > 0)
compute(Ctype, endNum-1);

if (Ctype)
{
return tempNum + endNum;
}
else
{
if (tempNum = 0)
tempNum = 1;

return tempNum * endNum;
}
}

int sum(int n)
{
if(n==1)
return 1;//出口

return sum(n-1)+n;
}
main()
{
int n=100;
printf("%d",sum(n));
}

#includ