C++ Newbie questions - c++

Question

My task:
Write the following program: The user is asked to enter 2 floating point numbers (use doubles). The user is then asked to enter one of the following mathematical symbols: +, -, *, or /. The program computes the answer on the two numbers the user entered and prints the results. If the user enters an invalid symbol, the program should print nothing.
My code:
#include <iostream>
using namespace std;
int introducir()
{
int a;
cin >> a;
return a;
}
bool simbolo(char x)
{
if (x == '+')
return true;
if (x == '-')
return true;
if (x == '*')
return true;
if (x == '/')
return true;
return false;
}
void operar(char x, int a, int b)
{
if (x == '+')
cout << a+b;
if (x == '-')
cout << a-b;
if (x == '*')
cout << a*b;
if (x == '/')
cout << a/b;
else cout << "INVALID OPERATION SIMBOL";
}
int main()
{
cout << "insert 2 numbers"<< endl;
int a =introducir();
int b= introducir();
cout << "introduce one of these simbols : +,-,* o /." << endl;
char x;
cin >> x;
bool primo= simbolo(x);
{
if (primo) {
cout << "simbol is valid" << endl;
} else {
cout << "invalid simbol" << endl;
}
cout << "operation result is:";
}
operar(x,a,b);
}
If the symbol is not in (+,-,*,/), I want it to return a message "INVALID OPERATION SIMBOL"; however it returns it even if the symbols are valid. How do I fix that?

Answer 1

The way you've written it, the else only applies to the final if.
Change to
if (x == '+'){
cout << a+b;
} else if (x == '-'){
cout << a-b;
} else if (x == '*'){
cout << a*b;
} else if (x == '/'){
cout << a/b;
} else {
cout << "INVALID OPERATION SIMBOL";
}
and similar for the other if statements. (You could even consider refactoring to a switch block.) The braces are not entirely necessary but I've put them in for clarity.