#include <iostream>
using namespace std;
 
int convert_to_decimal (long long num, int base) {
	int decimal_value = 0;
	int power = 1;
 
	while (num > 0) {
		int remainder = num % 10;
		num /= 10;
 
		if (remainder >= base) {
			std::cout << "Error: Invalid digit for the given base" << std::endl;
			return -1;
		}
 
		decimal_value += remainder * power;
		power *= base;
	}
	return decimal_value;
}
 
int main() {
	long long number_in_other_base;
	int base;
 
	std::cout <<"Enter the number in another base (e.g., 1011 for binary): ";
	std::cin >> base;
 
	int result =   convert_to_decimal(number_in_other_base, base);
 
	if (result != -1) {
		std::cout << number_in_other_base << " in base " << base << " is "
				  <<  result << " in decimal." << std::endl;
	}
 
	return 0;
}

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