Switches

[KirBy07]

Hey

Im' trying to make a thingy where you can add, subtract, devide and stuff using the switch statements.

In the middle of making it the thing wont compile. Something about 'jump to'.......
i dunno.




#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>

using namespace std;

int main ()

{


cout << "This program can do simple calculations for you. ";
cout << "\nChoose which you would like to do: ";
cout << "\n\nA. add";
cout << "\nB. subtract";
cout << "\nC. multiply";
cout << "\nD. devide";
cout << "\n\n\n Your choice: ";
char choice;
cin >> choice;

switch (choice)
{
case 'a':
case 'A':
int num, num2;
cout << "Ok you chose A";
cout << "\nEnter two numbers to add:";
cout << "\n First: ";
cin >> num;
cout << "\n Second: ";
cin >> num2;
int total = (num + num2);
cout << "\n Your total is: ";
cout << total;
cout << "\n\n";
break;

case 'b':
case 'B':
cout << "Ok you chose B";
cout << "\nEnter two numbers to subtract:";
break;

case 'c':
case 'C':
cout << "Ok you chose C";
cout << "\nEnter two numbers to multiply:";
break;

case 'd':
case 'D':
cout << "Ok you chose D";
cout << "\nEnter two numbers to devide:";
break;

}

system ("pause");
return 0;
}

[Danny]

My guess is that the following line causes this:

int total = (num + num2);


When you define variables and objects within a case block, always enclose the entire block with {} or better yet, call a function that does what is necessary. This will make your code look more structured and readable.

[KirBy07]

Ok i tried using a function. And the case thing.

but it doesnt work





int add (num, num2);
int sub (num, num2);
int mult (num, num2);
int div (num, num2);


int main ()

{


cout << "This program can do simple calculations for you. ";
cout << "\nChoose which you would like to do: ";
cout << "\n\nA. add";
cout << "\nB. subtract";
cout << "\nC. multiply";
cout << "\nD. devide";
cout << "\n\n\n Your choice: ";
char choice;
cin >> choice;

switch (choice)
{
case 'a':
case 'A':
{
int num, num2;
cout << "Ok you chose A";
cout << "\nEnter two numbers to add:";
cout << "\n First: ";
cin >> num;
cout << "\n Second: ";
cin >> num2;
total = add (num, num2);
cout << "\n Your total is: ";
cout << total;
cout << "\n\n";
break;
}

case 'b':
case 'B':
{
cout << "Ok you chose B";
cout << "\nEnter two numbers to subtract:";

break;
}

case 'c':
case 'C':
{
cout << "Ok you chose C";
cout << "\nEnter two numbers to multiply:";
break;
}



case 'd':
case 'D':
{
cout << "Ok you chose D";
cout << "\nEnter two numbers to devide:";
break;
}

}

system ("pause");
return 0;
}

add (num, num2)
{
total = num + num2;
return total;
}

[Danny]

where is the definition of total? and what's the exact error message you're getting?

[KirBy07]

I get errors like

redefinition
syntax
initializer
ISO C++

i dunno wat it is...





#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>

using namespace std;
int add (num, num2);
int sub (num, num2);
int mult (num, num2);
int div (num, num2);

int total;
int main ()

{


cout << "This program can do simple calculations for you. ";
cout << "\nChoose which you would like to do: ";
cout << "\n\nA. add";
cout << "\nB. subtract";
cout << "\nC. multiply";
cout << "\nD. devide";
cout << "\n\n\n Your choice: ";
char choice;
cin >> choice;

switch (choice)
{
case 'a':
case 'A':
{
int num, num2;
cout << "Ok you chose A";
cout << "\nEnter two numbers to add:";
cout << "\n First: ";
cin >> num;
cout << "\n Second: ";
cin >> num2;
total = add (num, num2);
cout << "\n Your total is: ";
cout << total;
cout << "\n\n";
break;
}

case 'b':
case 'B':
{
cout << "Ok you chose B";
cout << "\nEnter two numbers to subtract:";
cout << "\n First: ";
cin >> num;
cout << "\n Second: ";
cin >> num2;
total = sub (num, num2);
cout << "\n Your total is: ";
cout << total;
cout << "\n\n";
break;
}

case 'c':
case 'C':
{
cout << "Ok you chose C";
cout << "\nEnter two numbers to multiply:";
break;
}



case 'd':
case 'D':
{
cout << "Ok you chose D";
cout << "\nEnter two numbers to devide:";
break;
}

}

system ("pause");
return 0;
}

add (num, num2)
{
total = num + num2;
return total;
}

sub (num, num2)
{
total = num + num2;
}

mult (num, num2)
{
total = num * num2;
}

div (num, num2)
{
total = num / num2;
}

[Danny]

The problem lies in the declarations of yoru functions:

int add (num, num2);
int sub (num, num2);
int mult (num, num2);
int div (num, num2);


This style is obsolete. Change it to:

int add (int num, int num2);
int sub (int num, int num2);

and so on...

[KirBy07]

ok i did that stuff
am i not calling the functions correctly ?


#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>

using namespace std;
int add (int num, int num2);
int sub (int num, int num2);
int mult (int num, int num2);
int div (int num, int num2);

int main ()
{



cout << "This program can do simple calculations for you. ";
cout << "\nChoose which you would like to do: ";
cout << "\n\nA. add";
cout << "\nB. subtract";
cout << "\nC. multiply";
cout << "\nD. devide";
cout << "\n\n\n Your choice: ";
char choice;
cin >> choice;

switch (choice)
{
case 'a':
case 'A':
{
int num, num2, total;
cout << "Ok you chose A";
cout << "\nEnter two numbers to add:";
cout << "\n First: ";
cin >> num;
cout << "\n Second: ";
cin >> num2;
total = add (num, num2);
cout << "\n Your total is: ";
cout << total;
cout << "\n\n";
break;
}

case 'b':
case 'B':
{
int num, num2, total;
cout << "Ok you chose B";
cout << "\nEnter two numbers to subtract:";
cout << "\n First: ";
cin >> num;
cout << "\n Second: ";
cin >> num2;
total = sub (num, num2);
cout << "\n Your total is: ";
cout << total;
cout << "\n\n";
break;
}

case 'c':
case 'C':
{
int num, num2, total;
cout << "Ok you chose C";
cout << "\nEnter two numbers to multiply:";
cout << "\n First: ";
cin >> num;
cout << "\n Second: ";
cin >> num2;
total = mult (num, num2);
cout << "\n Your total is: ";
cout << total;
cout << "\n\n";
break;
}



case 'd':
case 'D':
{
int num, num2, total;
cout << "Ok you chose D";
cout << "\nEnter two numbers to devide:";
cout << "\n First: ";
cin >> num;
cout << "\n Second: ";
cin >> num2;
total = div (num, num2);
cout << "\n Your total is: ";
cout << total;
cout << "\n\n";
break;
}

}

system ("pause");
return 0;
}



add (num, num2)
{
total = num + num2;
return total;
}

sub (num, num2)
{
total = num + num2;
}

mult (num, num2)
{
total = num * num2;
}

div (num, num2)
{
total = num / num2;
}

[Danny]

No, the porblem is that you don't define them correctly:

add (num, num2) //bad
{
total = num + num2;
return total;
}


First, spell out the return type, which is int:

int add(...)
{
...
}

Then, define the parameters as in the declarations:

int add (int num, int num2)
{
total = num + num2;
return total;
}


Repeat these steps for all the functions you're using and then recompile.

[KirBy07]

ok the whole thing is redone.....
it should compile but its not, so i'm seriously lost


#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <string>

using namespace std;
void add(int, int);
void sub (int, int);
void mult (int, int);
void div (int, int);
void menu ();

int main ()
{
bool keepgoing=true;
int choice;

for (keepgoing=true);
{
cout << menu ()<<endl;
cout << "Your choice is: ";
cin >> choice;
if (choice == 5)||(choice!= 1,2,3,4)
{
cout << "Program Ended";
keepgoing = false;
}

else{
switch (choice)
case '1':
{
int num1, num2;
cout << "Enter two numbers to add";
cout << "First: ";
cin >> num1;
cout << "Second: ";
cin >> num2;
cout >> "\n\n\nYour answer is: "<<add (num1,num2)<<endl;
break;
}
case '2':
{
int num1, num2;
cout << "Enter two numbers to subtract";
cout << "First: ";
cin >> num1;
cout << "Second: ";
cin >> num2;
cout >> "\n\n\nYour answer is: "<<sub (num1,num2)<<endl;
break;
}
case '3':
{
int num1, num2;
cout << "Enter two numbers to multiply";
cout << "First: ";
cin >> num1;
cout << "Second: ";
cin >> num2;
cout >> "\n\n\nYour answer is: "<<mult (num1,num2)<<endl;
break;
}
case '2':
{
int num1, num2;
cout << "Enter two numbers to divide";
cout << "First: ";
cin >> num1;
cout << "Second: ";
cin >> num2;
cout >> "\n\n\nYour answer is: "<<div (num1,num2)<<endl;
break;
}
}
}
}


system ("pause");
return 0;
}

void add (int num1, int num2)
{
int total= num1 + num2;
cout << total << endl;
}

void menu ()
{
cout << " *****************Menu******************** ";
cout << " * * ";
cout << " * Choose what you would like to do: * ";
cout << " * * ";
cout << " * 1 ] Add * ";
cout << " * 2 ] Subtract * ";
cout << " * 3 ] Multiply * ";
cout << " * 4 ] Divide * ";
cout << " * 5 ] Quit * ";
cout << " ***************************************** ";
}

void sub (int num1, int num2)
{
int total= num1 - num2;
cout << total << endl;
}

void mult (int num1, int num2)
{
int total= num1 * num2;
cout << total << endl;
}

void div (int num1, int num2)
{
int total= num1 / num2;
cout << total << endl;
}

[Danny]

This is the problem:

for (keepgoing=true)

You probably mean:

while (keepgoing==true)
{
...
}

[Danny]

Also:

cout >> "\n\n\nYour answer is: "<<mult (num1,num2)<<endl;


THe return type of aqll your functions is void, which is no good in this case: you have to call a function that returns *some* value in a cout expression:

int mult(int n1, int n2);

cout >> "\n\n\nYour answer is: "<<mult (num1,num2)<<endl;


This should work.

[KirBy07]

dam....




#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <string>

using namespace std;
int add(int num, int num2);
int sub (int num, int num2);
int mult (int num, int num2);
int div (int num, int num2);
void menu ();

int main ()
{
bool keepgoing=true;
int choice;

while (keepgoing==true);
{
cout << menu ()<<endl;
cout << "Your choice is: ";
cin >> choice;
if (choice == 5)||(choice!= 1,2,3,4)
{
cout << "Program Ended";
keepgoing = false;
}

else{
switch (choice)
case '1':
{
int num1, num2;
cout << "Enter two numbers to add";
cout << "First: ";
cin >> num1;
cout << "Second: ";
cin >> num2;
cout << "\n\n\nYour answer is: "<<add (num1,num2)<<endl;
break;
}
case '2':
{
int num1, num2;
cout << "Enter two numbers to subtract";
cout << "First: ";
cin >> num1;
cout << "Second: ";
cin >> num2;
cout << "\n\n\nYour answer is: "<<sub (num1,num2)<<endl;
break;
}
case '3':
{
int num1, num2;
cout << "Enter two numbers to multiply";
cout << "First: ";
cin >> num1;
cout << "Second: ";
cin >> num2;
cout << "\n\n\nYour answer is: "<<mult (num1,num2)<<endl;
break;
}
case '2':
{
int num1, num2;
cout << "Enter two numbers to divide";
cout << "First: ";
cin >> num1;
cout << "Second: ";
cin >> num2;
cout << "\n\n\nYour answer is: "<<div (num1,num2)<<endl;
break;
}
}
}
}


system ("pause");
return 0;
}

int add (int num1, int num2)
{
int total= num1 + num2;
cout << total << endl;
}

void menu ()
{
cout << " *****************Menu******************** ";
cout << " * * ";
cout << " * Choose what you would like to do: * ";
cout << " * * ";
cout << " * 1 ] Add * ";
cout << " * 2 ] Subtract * ";
cout << " * 3 ] Multiply * ";
cout << " * 4 ] Divide * ";
cout << " * 5 ] Quit * ";
cout << " ***************************************** ";
}

int sub (int num1, int num2)
{
int total= num1 - num2;
cout << total << endl;
}

int mult (int num1, int num2)
{
int total= num1 * num2;
cout << total << endl;
}

int div (int num1, int num2)
{
int total= num1 / num2;
cout << total << endl;
}

[gorshing]

Could you post some error messages? The exact message please?

[gorshing]

Well, one problem is what Danny has already stated ...

The return type of aqll your functions is void, which is no good in this case: you have to call a function that returns *some* value in a cout expression

You are still doing that here ...

cout << menu ()<<endl;

The error message I received is ...

test.cpp(20) : error C2679: binary '<<' : no operator found which takes a right-
hand operand of type 'void' (or there is no acceptable conversion)

See how it gives you the exact line number where the error is at?

[KirBy07]

wat compiler are u using ?
cuz mine sux it gives me crappy error messages that dont mean anything.


anyways, the menu function i've done that before using void. so it should work.