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Cod sursa(job #374048)
#include <cstring>
#include <fstream>
#include <cstdlib>
#define LEVELMAX 2
#define NMAX 2000001
/*
*
*/
using namespace std;
ifstream in;
ofstream out;
const char op[4][4]={ "+-", "*/", "^", "" };
char e[NMAX], *expresion;
int evaluate( int a, char op, int b )
{
if( '+' == op )
return a+b;
if( '-' == op )
return a-b;
if( '*' == op )
return a*b;
if( '/' == op )
return a/b;
}
int evaluate( unsigned int level )
{int x, y;
if( LEVELMAX == level )
{
if( '(' == *expresion )
{
++expresion; //go over (
x=evaluate(0); //evaluate the new expresion from in the ( )
++expresion; //go over )
}
else for( x=0; *expresion >= '0' && *expresion <= '9'; ++expresion ) //if we have a number
x=x*10+*expresion-'0';
}
else for( x=evaluate(level+1); strchr( op[level], *expresion); x=y )
{char oper=*expresion; ++expresion;
y=evaluate( x, oper, evaluate(level+1) );
}
return x;
}
int main()
{
in.open("evaluare.in");
in>>e;
expresion=e;
out.open("evaluare.out");
out<<evaluate(0);
return 0;
}