求数列1，3/2!，5/3!，7/4!，9/5!……前n项之和。
求数列1，3/2!，5/3!，7/4!，9/5!……前n项之和。要求：求n!必须通过函数实现。输出格式不论，简单明了就好
2020-06-14 16:16
程序代码：double foo( unsigned n )
{
double result = 0;
double den = 1;
for( unsigned i=0; i!=n; ++i )
{
den *= i+1;
result += (2*i+1)/den;
}
return result;
}
#include <assert.h>
int main( void )
{
assert( foo(0) == 0 );
assert( foo(1) == 1 );
assert( foo(2) == 1+3.0/(1*2) );
assert( foo(3) == 1+3.0/(1*2)+5.0/(1*2*3) );
}
2020-06-15 09:20