int parentheses(int n, int l, int r, char *output)
{
int rvl = 0;
if (l == n)
{
while (n - r)
{
output[l + r] = ')';
r++;
}
rvl += 1;
int i;
printf("%s, ", output);
}
else
{
output[l + r] = '(';
rvl += parentheses(n, l + 1, r, output);
if (l > r)
{
output[l + r] = ')';
rvl += parentheses(n, l, r + 1, output);
}
}
return rvl;
}
bool Parser::atomic(std::string::iterator& iter, double& val)
{
auto localIter = iter;
double localValue = 0;
try
{
// Try to evaluate a number
if (number(localIter, localValue))
{
iter = localIter;
val = localValue;
return true;
}
// If there is no number then try to evaluate an expression
if (parentheses(localIter, localValue))
{
iter = localIter;
val = localValue;
return true;
}
return false;
}
// If there was an exception in parentheses function then rethrow it
catch (std::exception& e) { throw e; }
}
int main()
{
int n = 3;
char *output = malloc(sizeof(char)*(1+n));
output[n] = '\0';
int ret = parentheses(n, 0, 0, output);
printf("\n# of parentheses = %d\n", ret);
return 0;
}