C++ Boolean statement errors (I think) - c++

Question

This program is supposed to ask for an integer, if you want to add or subtract, then another integer, then do the math, but it declares both subtraction and addition as false inputs and i think there are errors in my boolean. Any help is appreciated.
/***********************************************************
Program Name: Simple Math Calculator
Program Author: Kyle NoCompile
Date Created: 9/12/16
Program Description:
This program performs simple arithmetic calculations.
The user enters numbers and the math operation to
perform on those numbers. The program will then display
the result of the operation.
Modified Date:
Modified Description:
***********************************************************/
#include <iostream>
using namespace std;
// Function prototypes:
void showWelcome();
int getUserIntegerInput();
char getMathChoice();
int getInteger(bool);
bool validateMathChoice(char choice);
int doAddition(int int1, int int2);
int doSubtraction(int int1, int int2);
int doMath(int firstInt, int secondInt, char mathFunc);
int showResult();
// This is the main function (where the program begins)
int main()
{
// Variables to hold local data
int firstNum;
int secondNum;
int mathChoice;
int result;
// Call the showWelcome() function
void showWelcome();
// Call the getInteger() function (for the first integer)
// and store the result in the "firstNum" variable
firstNum = getInteger(true);
// Call the getMathChoice() function and store result in "mathChoice" variable
mathChoice = getMathChoice();
// Call validateMathChoice() function, passing it the user's math choice
// and using the return value to decide what to do next
if (validateMathChoice() = true)
{
// Call the getInteger() function (for the second and subsequent integers)
// and store the result in the "secondNum" variable
secondNum = getInteger(false);
// Call the doMath() function and pass it all of the user input
// and store the return value in the "result" variable.
int result = doMath(firstNum,secondNum,mathChoice);
// Call the showResult() function to show the result
int showResult(int result);
}
else
{
// If the user chose an invalid math function...
cout<<"Not a valid math choice"<<endl;
}
return 0;
}
// This function shows a nice welcome message
void showWelcome()
{
cout<<"******************************************"<<endl;
cout<<"Welcome to the simple calculator program!"<<endl;
cout<<"This program will do simple addition and"<<endl;
cout<<"subtraction. Math is fun, so enjoy!"<<endl;
cout<<"******************************************"<<endl;
}
// This function gets integer input from the user
int getUserIntegerInput()
{
int input;
cin>>input;
return input;
}
// This function asks the user for a math function
// and returns the user's input
char getMathChoice()
{
char choice;
cout<<endl<<"Please select a math function to perform (\"+\" = Addition, \"-\" = Subtraction): ";
cin>>choice;
return choice;
}
// this function asks the user for either the first integer
// or the second and returns the user's input
int getInteger(bool firstNum)
{
cout<<endl<<"Please enter the ";
// if the "firstNumber" variable is true, then this
// is the first number being collected
if (firstNum)
{
cout<<"first ";
}
// Otherwise, it's the second number being collected
else
{
cout<<"second ";
}
cout<<"integer: ";
// Call the getUserIntegerInput() function and return the return value from it
return getUserIntegerInput();
}
// This function validates the user's match function choice
// by returning a true for valid, and a false for invalid
bool validateMathChoice(char choice)
{
if (choice == '+' || choice == '-')
{
return true;
}
else
{
return false;
}
}
// This function adds two integers
int doAddition(int firstInt,int secondInt)
{
return firstInt + secondInt;
};
// This function subtracts the second integer
// parameter from the first integer parameter
int doSubtraction(int firstInt, int secondInt)
{
return firstInt - secondInt;
};
// This function determines the result of the math
// operation requested by the user
int doMath(int firstInt, int secondInt, char mathFunc)
{
// Initialize result to zero (0)
int result = 0;
// If the math function is a "+", then call the
// doAddition() function and store the return
// value in the "result" variable
if (mathFunc = '+')
{
result = doAddition(firstInt, secondInt);
return result;
}
// If the math function is a "-", then call the
// doSubtraction() function and store the return
// value in the "result" variable
else (mathFunc = '-');
{
result = doSubtraction(firstInt, secondInt);
return result;
}
return result;
}
// This function displays the result of a math operation
int showResult(int result)
{
cout<<endl<<"The result is "<<result<<endl;
}