实现1/1-1/2+1/3-1/4+…+1/100的和。
#include <stdio.h>
#define SIGN(x) ((x) > 0 ? 1 : ((x) < 0 ? -1 : 0))
#define ABS(x) ((x) >= 0 ? (x) : -(x))
typedef long long LL;
LL gcd(LL a, LL b)
{
return b ? gcd(b, a % b) : a;
}
typedef struct
{
LL up;
LL down;
} FRACTION;
void simplify(FRACTION *f)
{
if (f->up == 0)
{
f->up = 0;
f->down = 1;
}
else if (SIGN(f->up) * SIGN(f->down) > 0)
{
f->up = ABS(f->up);
f->down = ABS(f->down);
}
else
{
f->up = -ABS(f->up);
f->down = ABS(f->down);
}
LL g = gcd(ABS(f->up), f->down);
f->up /= g;
f->down /= g;
}
void input(FRACTION *f)
{
scanf("%I64d%I64d", &f->up, &f->down);
simplify(f);
}
void print(FRACTION *f)
{
if (f->down == 1)
printf("%I64d ", f->up);
else
printf("%I64d/%I64d ", f->up, f->down);
}
void testSimplify()
{
FRACTION a = {4, -6}, b = {-8, -6}, c = {99, 66}, d = {0, -5};
simplify(&a), simplify(&b), simplify(&c), simplify(&d);
print(&a), print(&b), print(&c), print(&d);
}
LL add(FRACTION*a,FRACTION*b,FRACTION*c)
{
LL up=a->up*b->down+a->down*b->up;
LL down=a->down*b->down;
c->up=up;
c->down=down;
simplify(c);
}
void testAdd()
{
FRACTION a = {4, -6}, b = {-8, -6}, c;
add(&a, &b, &c);
print(&c);
}
int main()
{
int i;
FRACTION s= {0,1};
for(i=1; i<=100; i++)
{
if(i%2==0)FRACTION cur= {-1,i};
FRACTION cur= {1,i};
add(&s,&cur,&s);
}
print(&s);
return 0;
}