Prea multe explicatii nu-ti trebuie pt ecuatia de gradul al II-lea. Daca sti formula ec de grII ai s-o intelegi. Succes!
#include <bits/stdc++.h>
using namespace std;
char c[20];
int n, i, j, a, b, cc, d;
double x1, x2, s;
bool semn;
int main()
{
ifstream f("ecuatii.in");
ofstream g("ecuatii.out");
f >> c;
while(i < strlen(c))
{
if(c[i] == 'x' && c[i + 1] == '^')
{
if(n == 0 && (c[i - 1] == '-' || c[i - 1] == '+' || i == 0)) n = 1;
if(semn == 0) a = a + n;
else a = a - n;
n = 0;
i = i + 2;
}
else if(c[i] == 'x')
{
if(n == 0 && (c[i - 1] == '-' || c[i - 1] == '+' || i == 0)) n = 1;
if(semn == 0) b = b + n;
else b = b - n;
n = 0;
}
else if(c[i] == '+') semn = 0;
else if(c[i] == '-') semn = 1;
else n = n * 10 + (c[i] - '0');
i ++;
}
if(semn == 0) cc = cc + n;
else cc = cc - n;
d = b * b;
d = d - (4 * a * cc);
if(d < 0) g << -1;
else if(d == 0)
{
x1 = -b;
x1 = double(x1) / (2 * a);
g << fixed << setprecision(2) << x1;
}
else
{
s = double(sqrtl(d));
x1 = -b;
x1 = x1 - s;
x1 = double(x1) / (2 * a);
x2 = -b;
x2 = x2 + s;
x2 = double(x2) / (2 * a);
if(x1 < x2)
{
g << fixed << setprecision(2) << x1 << " ";
g << fixed << setprecision(2) << x2 << '\n';
}
else
{
g << fixed << setprecision(2) << x2 << " ";
g << fixed << setprecision(2) << x1 << '\n';
}
}
return 0;
}
