int tam_infijo (char * array){
int cont = 0;
while ( *( array + cont ) != '\0' ){
cont++;
}
return cont - 1;
}
char * scan_infijo (){
char * expresion;
expresion
= (char*) calloc (200, sizeof (char));
fgets (expresion
, 200, stdin
);
realloc (expresion
, sizeof(char) * (tam_infijo
(expresion
) + 1) );
}