help calculation code kinda

[Nubre]

OK so I'm a complete noon in c and this is my first forum post :)
I've been making a calculating code for some time and changing/ adding stuff to it now I want to add an option where after you get the answer it asks you if you would like to multiply the answer..this is what I've come up with and I know its totally wrong but this is how I learn best, I just try to make with what I know lol, (BTW c++ is my first language I'm learning, I know most recommend something easier as python)
Now I know this is totally wrong and weird :)

  

int main(void)
{
     int num1;
     int num2;
     int sum;
     int sum2;
     int answer;
     int yes;

     printf("Enter your number:");
    
     scanf("%d", &num1);
     scanf("%d", &num2);
    
     sum = num1 + num2;
    
     printf("the sum is %d", sum);
     printf("would you like to multiply that?");
     
     if(answer == yes);
     sum2 = sum * sum
     printf("Here you go:\n %d", sum2);

     else
     printf("To bad..");

    
      getchar();

     }

[o3hC5Di1]

Hi there,

The program you showed us is in C - not C++.
If C++ is what you're learning, I recmmend you use the C++ streams for input and output:
http://www.cplusplus.com/doc/tutorial/basic_io/

Otherwise, you probably want curly braces around your if/else blocks:

if(answer == yes);
{
     sum2 = sum * sum
     printf("Here you go:\n %d", sum2);
}
else
{
     printf("To bad..");
}

You are only allowed to omit curly braces if both the if-block and else-block only consist of one statement:

if(answer == yes)
     printf("Here you go:\n %d", sum*sum);
else
     printf("To bad..");

Hope that helps, please do let us know if you have any further questions.

All the best,
NwN

[nvrmnd]

if(answer == yes);

This will not work since you haven't initialized the value of them, or either changed it anywhere in your code

[JLBorges]

#include <stdio.h>

int main()
{
     printf("Enter your numbers:");

     int num1;
     int num2;
     scanf("%d", &num1);
     scanf("%d", &num2);

     const int sum = num1 + num2;
     printf("the sum is %d\n", sum);

     const int yes = 1 ;
     printf("would you like to square that (1==yes)?");
     int answer;
     scanf("%d", &answer);

     if(answer == yes) // ; removed
     {
         const int square = sum * sum ; // **** ; added

         printf("Here you go: %d\n", square);
     }

     else printf("Too bad..");

     getchar();
}

[Nubre]

Thanks so much for the answers!

Can anyone further explain const int? Why not just int?

and how come you didn't declare "sum"

[Ayodeji Joel]

i think const int is the constant int,............... like the one whose value you've already set

int a;
a=6;

[Nubre]

But as you can see in the code jlborges posted "sum" is not set to any value yet he uses "const int sum"


well, after playing around i got to this thanks for the help guys

#include <stdio.h>
#include <stdafx.h>


int main()
{
printf("Enter your numbers:\n");

int num1;
int num2;
scanf_s("%d", &num1);
printf("+\n");
scanf_s("%d", &num2);

const int sum = num1 + num2;
printf("= \n%d\n", sum);

const int yes = 1 ;
printf("would you like to square that? 1 = yes 2 = no\n");
int answer;
scanf_s("%d", &answer);

if(answer == yes)
{
const int square = sum * sum ;

printf("Here you go: %d\n", square);
}

else printf("Too bad..");

getchar();
}

[nvrmnd]

Can anyone further explain const int

the const keyword makes a variable read-only -> ( the value cannot be changed, it can only be determined at the time it was created:

const int var = 1234;
var = 2; // Will produce a compiler error !

int bla = 1234;
bla = 1; // Okay  

[JLBorges]

A const int is an int that
a. must be initialized
b. once initialised, the value cannot be changed


> "sum" is not set to any value yet he uses "const int sum"

const int sum = num1 + num2; // initializes 'sum' with the value of 'num1 + num2'
// ...
const int yes = 1 ; // initializes 'yes' with the value 1 

After that, 'sum' and 'yes' can't be changed.

sum = 0 ; // *** error: we can't modify a constant

[Nubre]

awesome, thanks alot for the explanation jlborges!, and shadow :O