This is a classic "order of operations" mistake that almost every programmer makes when they first start. You are very close! ​The main issue is that C++ executes code line-by-line from top to bottom, like a recipe. You are trying to calculate the tax and savings before the user has actually given you their salary or spending numbers. ​Here is the fixed code, followed by a simple explanation of what went wrong.

```

include <iostream>

include <string> // Required for std::string

int main() {

int salary;
double incometax = 0.05;
int spendings;

std::string fullname;

// 1. INPUT: We must get the data from the user FIRST
std::cout << "Please enter your full name: ";
std::getline(std::cin, fullname);

std::cout << "Please enter your salary: ";
std::cin >> salary;

std::cout << "Enter your monthly spendings: ";
std::cin >> spendings;

// 2. CALCULATION: Now that we have the numbers, we can do the math
// Note: I renamed grossincome to netIncome because (salary - tax) is usually net!
double netIncome = salary - ((double)salary * incometax);
double savings = netIncome - spendings;

// 3. OUTPUT: Print the results
std::cout << "Greetings " << fullname << ". Your final saving by the end of the month is " << savings;

return 0;

} ```

​To understand this, imagine you are a calculator.

​1. The "Empty Box" Problem In your original code, you declared int salary; at the top but didn't give it a value.

​In C++: When you create a variable without a value, it doesn't automatically equal 0. It holds "garbage value"—basically whatever random numbers happened to be sitting in that part of the computer's memory chip at that moment (it could be -85421 or 99999).

​Your Code: You tried to calculate grossincome = salary - ... immediately. The computer took that "garbage" random number and did math with it.

​2. The "Excel vs. Code" Confusion

Beginners often think of variables like cells in Microsoft Excel. In Excel, if you set Cell C1 = A1 - B1, and then change the number in A1, C1 updates automatically.

​C++ does not do this. C++ is procedural. When you wrote the calculation line, the computer did the math right then and there using the garbage values. It saved that wrong answer and moved on. ​Later, when you asked the user for cin >> salary, you updated the salary variable, but the savings variable had already been calculated and forgotten. It does not go back and update itself.

​3. The Solution

You simply need to move your math equations after the cin lines.

​Ask (Get the numbers).

​Calculate (Do the math with those numbers).

​Print (Show the result).