CAN YOU PLEASE GUIDE ME WHY I AM GETTING THIS ERROR AND HELP FIX THE CODE

Instructions

$**($Fraction calculator$)**|$ Write a program that lets the user perform arithmetic operations on fractions. Fractions are of the form a$/$b$,$ in which a and b are integers and b $0.$ Your program must be menu driven, allowing the user to select the operation $(+,,*,$ or $/)$ and input the numerator and denominator of each fraction. Furthermore, your program must consist of at least the following functions:

Function menu: This function informs the user about the program$$s purpose, explains how to enter data, and allows the user to select the operation.

Function addFractions: This function takes as input four integers representing the numerators and denominators of two fractions, adds the fractions, and returns the numerator and denominator of the result. $($Notice that this function has a total of six parameters.$)$

Function subtractFractions: This function takes as input four integers representing the numerators and denominators of two fractions, subtracts the fractions, and returns the numerator and denominator of the result. $($Notice that this function has a total of six parameters.$)$

Function multiplyFractions: This function takes as input four integers representing the numerators and denominators of two fractions, multiplies the fractions, and returns the numerators and denominators of the result. $($Notice that this function has a total of six parameters.$)$

Function divideFractions: This function takes as input four integers representing the numerators and denominators of two fractions, divides the fractions, and returns the numerator and denominator of the result. $($Notice that this function has a total of six parameters.$)$ Some sample outputs are:

$**3/4+2/5=23/20**$

$2/3*3/5=6/15$

Your answer need not be in the lowest terms.

CODE#

#include

using namespace std;

void menu$()\{$

cout $<<$ "This program lets you perform arithmetic operations on fractions." $<<$ endl;

cout $<<$ "Enter the numerator and denominator of each fraction, separated by a space." $<<$ endl;

cout $<<"$To add two fractions, enter $\text{'}+\text{'}"<<$ endl;

cout $<<"$To subtract two fractions, enter $\text{'}-\text{'}"<<$ endl;

cout $<<"$To multiply two fractions, enter $\text{'}*\text{'}"<<$ endl;

cout $<<"$To divide two fractions, enter $\text{'}/\text{'}"<<$ endl;

cout $<<"$To quit the program, enter $\text{'}$q$\text{'}"<<$ endl;

$\}$

void addFractions$($int num$1,$ int den$1,$ int num$2,$ int den$2,$ int &num, int &den$)\{$

num $=$ num$1*$ den$2+$ num$2*$ den$1$;

den $=$ den$1*$ den$2$;

$\}$

void subtractFractions$($int num$1,$ int den$1,$ int num$2,$ int den$2,$ int &num, int &den$)\{$

num $=$ num$1*$ den$2-$ num$2*$ den$1$;

den $=$ den$1*$ den$2$;

$\}$

void multiplyFractions$($int num$1,$ int den$1,$ int num$2,$ int den$2,$ int &num, int &den$)\{$

num $=$ num$1*$ num$2$;

den $=$ den$1*$ den$2$;

$\}$

void divideFractions$($int num$1,$ int den$1,$ int num$2,$ int den$2,$ int &num, int &den$)\{$

num $=$ num$1*$ den$2$;

den $=$ den$1*$ num$2$;

$\}$

int gcd$($int a$,$ int b$)\{$

while $($b $!=0)\{$

int temp $=$ a;

a $=$ b;

b $=$ temp $\%$ b;

$\}$

return a;

$\}$

void simplifyFraction$($int &num, int &den$)\{$

int gcd$\_$value $=$ gcd$($num$,$ den$)$;

num $/=$ gcd$\_$value;

den $/=$ gcd$\_$value;

$\}$

int main$()\{$

menu$()$;

while $($true$)\{$

char operation;

cout $<<$ "Enter an operation $(+,-,*,/,$ or q to quit$)$: $"$;

cin $>>$ operation;

if $($operation $==\text{'}$q$\text{'})\{$

break;

$\}$ else if $($operation $==\text{'}+\text{'}||$ operation $==\text{'}-\text{'}||$ operation $==\text{'}*\text{'}||$ operation $==\text{'}/\text{'})\{$

int num$1,$ den$1,$ num$2,$ den$2$;

cout $<<$ "Enter the first fraction: $"$;

cin $>>$ num$1>>$ den$1$;

cout $<<$ "Enter the second fraction: $"$;

cin $>>$ num$2>>$ den$2$;

int num, den;

if $($operation $==\text{'}+\text{'})\{$

addFractions$($num$1,$ den$1,$ num$2,$ den$2,$ num, den$)$;

$\}$ else if $($operation $==\text{'}-\text{'})\{$

subtractFractions$($num$1,$ den$1,$ num$2,$ den$2,$ num, den$)$;

$\}$ else if $($operation $==\text{'}*\text{'})\{$

multiplyFractions$($num$1,$ den$1,$ num$2,$ den$2,$ num, den$)$;

$\}$ else if $($operation $==\text{'}/\text{'})\{$

divideFractions$($num$1,$ den$1,$ num$2,$ den$2,$ num, den$)$;

$\}$

simplifyFraction$($num$,$ den$)$;

cout $<<$ num$1<<"/"<<$ den$1<<""<<$ operation $<<""<<$ num$2<<"/"<<$ den$2<<"="<<$ num $<<"/"<<$ den $<<$ endl;

$\}$

$\}$

return $0$;

$\}$