C++ Calculator

[ember island]

#include <iostream>

std::string getOperator() {
    int operandDecider;
    std::string whichOperator;
    std::cout << "What operation would you like to compute (sub, add, div, mul)?: ";
    std::cin >> whichOperator;
    return whichOperator; }

int assignInt(){
    int operandDecider;
    if (whichOperator == "add") {
        operandDecider = 1; 
    } else if (whichOperator == "sub") {
        operandDecider = 2;
    } else if (whichOperator == "mul") {
        operandDecider = 3;
    } else if (whichOperator == "div") {
        operandDecider = 4;
    }

    return operandDecider;
}


void process(){
    int num1;
    int num2;
    std::cout << "Enter num1: ";
    std::cin >> num1;
    std::cout << "Enter num2: ";
    std::cin >> num2;
    if (operandDecider == 1)
    {
        std::cout << num1 + num2;
    }
  }
int main() {
    getOperator()
    assignInt()
    process();
    return 0;
}```

Red lines, how do I fix?

[azure plank]

local variable "whichOperator" does not exist in the context of assignInt

same for process but with operandDecider

you need to either take in an argument or initialize a local variable of the same name in the functions

you honestly don't need those functions the way you wrote main

just put everything in main

[ember island]

how does that look like?

[ember island]

yeah, but im trying to learn functions more

[ember island]

how would code look like?

[azure plank]

arguments go in the parantheses

int foo(int arg);

[ember island]

ye

[azure plank]

arg is an argument

[ember island]

ok

[azure plank]

thats how you create an argument for a function

just make sure to write the datatype and argument name

you want multiple

you can separate them by commas

[ember island]

i need to do std::string whichOperator?

oh ok

[azure plank]

if you want to use it as an argument, then yeah put that in the parantheses

local variables are just variables that are defined inside of the function

only that function can use them

[ember island]

like this?

[azure plank]

yes

when you call the functions

[ember island]

i get red at bottom btw

ye

[azure plank]

make sure to also put in the arguments

[ember island]

why?

[azure plank]

arguments are things you use when you want a different input to produce a different output

so if i had the function

[ember island]

nani

[azure plank]

int addFive(int num)
{
  return num+5;
}

int main()
{
  addFive(10); //would return 15
  addFive(15); //Would return 20
}

you pass in a value into the function call to be used as an argument inside the function

[azure plank]

that value can be a variable or just a value like here

btw u should probably check out

https://www.w3schools.com/cpp/

[ember island]

https:/learncpp.com?

[azure plank]

that's also a good resource

[ember island]

damn its big confusing idk why

bit

[azure plank]

so i initialize a function

addFive

and i give it an argument it can take

num

[ember island]

https://www.learncpp.com/cpp-tutorial/introduction-to-function-parameters-and-arguments/

i found this

[ember island]

you mean

call function addFive

?

[azure plank]

that works as well

initialize

[ember island]

oh like define?

[azure plank]

or not really initialize

but define

yeah

[ember island]

ok

oh ok I will check this link

thanks for help!!!

i understand it better

[hushed smelt]

please dont use else if, else if, else if, else if

just use a switch statement

thanks

[nova shuttle]

doesn't work with strings

a lookup unordered map is the best option probably

[ember island]

o ye

what to do?

[nova shuttle]

are you familiar with hash tables/maps?

[ember island]

nope

#include <iostream>

int chooseOperator(){
    std::string operatorInput;
    std::cout << "What operator would you like to use (sub, div, add, mul?: )";
    std::cin >> operatorInput;
    
    int operandDecider;
    if (operatorInput == "sub")
        operandDecider = 1;
    
    else if (operatorInput == "div")
        operandDecider = 2;
    
    else if (operatorInput == "add")
        operandDecider = 3;

    else if (operatorInput == "mul")
        operandDecider = 4;

    return operandDecider;
}

void process(int operandDecider, int num1, int num2){

    switch (operandDecider)
    {
    case 1:
       std::cout << num1 - num2;
        break;
    case 2:
       std::cout << num1 / num2;
        break;
    case 3:
        std::cout << num1 + num2;
        break;
    case 4: 
      std::cout << num1 * num2;
        break;
    default:
        break;
    }

}

int main(){
int num1;
int num2;
int operandDecider;
std::cout << "Calculator\n";
std::cout << "Enter number 1: ";
std::cin >> num1;
std::cout << "Enter number 2: ";
std::cin >> num2;
chooseOperator();
process(operandDecider, num1, num2);

    return 0;
}```

[nova shuttle]

that's not really solving the problem, just moving it to a different place

take a look at std::unordered_map

[hushed smelt]

completly forgor about that