Solve the equation
Problem to find the x value in given equation. The equation perform the arithmatic operation "+" and "-" only.
Example-1:
Input : n = "x+5=10" Output : 5 Explain : x + 5 = 10 x = 10-5 x = 5
Example-2:
Input : n = "10+5=-x+2" Output : -13 Explain : 10+5=-x+2 10+5-2=-x 13=-x x=-13
Example-3:
Input : n = "1+2=-2+4+x" Output : 1 Explain : 1+2=-2+4+x 3-2=x x=1
Solution
public class Main
{
public static void main(String[] args)
{
String s = "10+5=-x+2";
int value = 0;
boolean f = false, x_lhs = false;
for (int i=0;i<s.length();i++)
{
if(isNum(s.charAt(i)))
{
int a = 0;
if(i != 0 && s.charAt(i-1)=='-')
{
while(i<s.length() && isNum(s.charAt(i)))
{
a = (a*10) + Character.getNumericValue(s.charAt(i));
i++;
}
if(f) value = value + a;
else
{
value = value-a;
}
}
else
{
while(i<s.length()&&isNum(s.charAt(i)))
{
a = (a*10) + Character.getNumericValue(s.charAt(i));
i++;
}
if(f) value = value-a;
else
{
value = value + a;
}
}
i--;
}
if(s.charAt(i)=='=') f = true;
if(!f&&s.charAt(i)=='x')
{
x_lhs = true;
if(i!=0&&s.charAt(i-1)=='-') x_lhs = false;
}
if(f&&s.charAt(i)=='x'&&s.charAt(i-1)=='-') x_lhs=true;
}
if(x_lhs) System.out.println(-value);
else
{
System.out.println(value);
}
}
public static boolean isNum(char c)
{
if(c >= '0' && c<='9') return true;
return false;
}
}
Output
5