ex01: init

ex01/src/RPN.cpp

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+#include <stack>
+#include <iostream>
+
+

ex01/src/main.cpp

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+#include <cctype>
+#include <cstddef>
+#include <iostream>
+#include <string>
+#include <stack>
+#include <cstring> 
+
+int substraction(int a, int b) {	return (a - b); }
+int addition(int a, int b) {	return (a + b); }
+int division(int a, int b) {	return (a / b); }
+int multiplication(int a, int b) {	return (a * b); }
+
+int calculate(std::stack<int>& nums, std::stack<char>& operators)
+{
+	if (nums.size() < 2 || operators.size() == 0)
+		return 0;
+
+	int ret;
+	int a = nums.top();
+	nums.pop();
+	int b = nums.top();
+	nums.pop();
+	
+	switch (operators.top()) {
+		case '+':
+			ret = addition(a, b);
+			break;
+		case '-':
+			ret = substraction(a, b);
+			break;
+		case '*':
+			ret = multiplication(a, b);
+			break;
+		case '/':
+			if (b == 0)
+				return 1;
+			ret = division(a, b);
+			break;
+	}
+	operators.pop();
+	nums.push(ret);
+	return 0;
+}
+
+int main(int ac, char** av)
+{
+	if (ac != 2)
+	{
+		std::cout << "error: args" << std::endl;
+		return 1;
+	}
+
+	std::stack<int> nums;
+	std::stack<char> operators;
+
+	for (size_t i = 0; av[1][i] != '\0'; i++)
+	{
+		if (av[1][i] == ' ')
+			continue;
+		if (std::isdigit(av[1][i]))
+			nums.push(av[1][i] - '0');
+		else if (std::strchr("/+-*", av[1][i]) != NULL)
+			operators.push(av[1][i]);
+		else
+		{
+			std::cout << "error: '" << av[1][i] << "' unknown char" << std::endl;
+			return 1;
+		}
+		if (calculate(nums, operators))
+		{
+			std::cout << "error: division by 0" << std::endl;
+			return 1;
+		}
+	}
+	if (nums.size() != 1)
+	{
+		std::cout << "error: too many numbers" << std::endl;
+		return 1;
+	}
+	if (operators.size() != 0)
+	{
+		std::cout << "error: too manu operators" << std::endl;
+		return 1;
+	}
+	std::cout << nums.top();
+	return 0;
+}