Calculator Syntax Error

[zajohnson]

Hello guy, i'm new here so i don't exactly know how thing are run. But anyways i was trying to create a basic calculator but i kept getting the error, "Syntax error at end of input" every time i tried to compile and run it.
If you guys could take a look and see where my mistake was, it would be greatly appreciated.

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <math.h>


int Addition(int x, int y);
int Subtraction(int x, int y);
int Multiplication(int x, int y);
int Division(int x, int y);


int main( void ) {
    int choice;
    int num1;
    int num2;
    int answer;
    int exit;
    
    int x;
    int y;
    
    int yes = 0;
    int no = 1;


    Start:
          
    system("CLS");
    system("COLOR 4F");
    
    printf("                              Welcome to Zach's Commandline Equation Calculator!\n");
    printf("\n\nInsert the number of the type of equation you wish to be calculated:\n");
    printf("1- Addition\n");
    printf("2- Subtraction\n");
    printf("3- Multiplication\n");
    printf("4- Division\n");
    printf("5- Exit Calculator");
    
    scanf("%d,\n", &choice, "\n");
    
    switch(choice)
    {
    
    case 1:
         
         printf("\n");
         scanf("%d%d", &num1, &num2);
         
         printf("\n\n%d", addition(num1, num2));
         getchar();
         goto Start;
         break;
         
    case 2:
         
         printf("\n");
         scanf("%d%d", &num1, &num2);
         
         printf("\n\n%d", subtraction(num1, num2));
         getchar();
         goto Start;
         break;
         
    case 3:
         
         printf("\n");
         scanf("%d%d", &num1, &num2);
         
         printf("\n\n%d", multiplication(num1, num2));
         getchar();
         goto Start;
         break;
         
    case 4:
         
         printf("\n");
         scanf("%d%d", &num1, &num2);
         
         printf("\n\n%d", division(num1, num2));
         getchar();
         goto Start;
         break;
         
    case 5:
         
         printf("\nAre you sure you want to exit from this operation?\n");
         printf("\n0 - yes\n1 - no");
         
         scanf("%d", &exit);
         
         if(exit == yes)
         {
           system("EXIT");
           }
         else if (exit == no)
         {
           goto Start;
           }
         else
         {
           goto Start;
           }
           break;
         default:
           {
                 goto Start;
                 break;
                   }
 
  getch();
  return 0;
}

Also, any improvements would be greatly appreciated.

[Adak]

Do you see how the word exit is colored in your code? That's because exit is a keyword in C - you can't use it for the name of a variable.

You have a nice general program, but then there are the goto's aren't there? >.<

Two suggestions - 1) learn what your compiler errors really mean, so you can find simple errors in your code and 2) learn to structure your programs using loops and or functions, instead of goto's.

I'm not a no-goto fanatic, but on a larger program, goto's can be *massive* headaches when you need to extend or debug code.


And Welcome to the Forum! XD

[zajohnson]

Which exit?

This?

if(exit == yes)

Or this?

system("EXIT");

BTW, a friend helped me with the goto's and i replaced them with

main();

[quzah]

Which exit?

the name of a variable.

Quzah.

[zajohnson]

Sorry to keep this thread alive but now get a new error. I fixed the syntax error and input the functions but now every time i go to input the to numbers to see if it works it goes straight back to Start:. BTW The exit command works just fine, just the addition, subtraction, etc. don't.

Can you tell me what i need to change?

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <math.h>


int Addition(int x, int y);
int Subtraction(int a, int b);
int Multiplication(int c, int d);
int Division(int e, int f);


int main( void ) {
    int choice;
    int num1;
    int num2;
    int answer;
    int leave;
    
    int x;
    int y;
    
    int yes = 0;
    int no = 1;


    Start:
          
    system("CLS");
    system("COLOR 4A");
    
    printf("                 Welcome to Zach's Commandline Equation Calculator!\n");
    printf("\n\nInsert the number of the type of equation you wish to be calculated:\n");
    printf("1- Addition\n");
    printf("2- Subtraction\n");
    printf("3- Multiplication\n");
    printf("4- Division\n");
    printf("5- Exit Calculator\n\n");
    
    scanf("%d,\n", &choice, "\n");
    
    switch(choice)
    {
    
    case 1:
         
         printf("\nInput the two numbers you wish to add here then press Enter:");
         scanf("%d %d", &num1, &num2);
         int x = num1;
         int y = num2;
         answer = num1 + num2;   
         getchar();
         main();
         break;
         
    case 2:
         
         printf("\nInput the two numbers you wish to subtract here then press Enter:");
         scanf("%d %d", &num1, &num2);
         int a = num1;
         int b = num2;
         answer = num1 - num2;
         getchar();
         main();
         break;
         
    case 3:
         
         printf("\nInput the two numbers you wih to be multiplied here then press Enter:");
         scanf("%d %d", &num1, &num2);
         int c = num1;
         int d = num2;
         answer = num1 * num2;
         getchar();
         main();
         break;
         
    case 4:
         
         printf("\nInput the two numbers you wish to be divided here then press Enter:");
         scanf("%d %d", &num1, &num2);
         int e = num1;
         int f = num2;
         answer = num1 / num2;
         getchar();
         main();
         break;
         
    case 5:
         
         printf("\nAre you sure you want to exit from this operation?\n");
         printf("\n0 - yes\n1 - no\n");
         
         scanf("%d", &leave);
         
         if(leave == yes)
         {
           exit(0);
           }
         else if (leave == no)
         {
           main();
           }
         else
         {
           main();
           }
           break;
         default:
           {
                 main();
                 break;
                   }


  getchar();
  return 0;
}


}

[quzah]

You are recursively calling main. That's bad. Just use a loop:

do
    get input
    check input
    use input
while input is not whatever you use to quit

http://www.cprogramming.com/tutorial/c/lesson3.html


Quzah.

[anduril462]

• Get rid of the Start: on line 27, since you're no longer using goto.
• Never call main recursively. Remove all those. Use a loop to repeat your program (example below).
• You never print the answer.
• Get rid of all the useless variable declarations inside the switch cases: x, y, a, b, etc. You never use them.
• Your default case should print invalid choice, so the user knows what the problem was.

Example:

int done = 0;  // set done to false
...
do {
    print menu
    get choice from user
    switch (choice)
    {
        ...
        case 5:
            ask if they're sure
            if they're sure, set done to true
            break;
    }
} while (!done);

[zajohnson]

Does this apply to every case or just case 5?

[anduril462]

Does what apply to every case? Remove the recursive call to main from every case. Remove the unused variables from every case. Print the answer in every case that produced an answer. Case 5 is the only case for quitting, so that's the only case you ask "Are you sure you want to quit?" and the only case where you set done to true.