help with c++

This is a discussion on help with c++ within the C++ Programming forums, part of the General Programming Boards category; Code: #include<stdio.h> int main() { char ans; int month,food,trans,eqp,misc; float total=0,over=0; do { printf("Enter your monthly allowance:"); scanf("%d",&month); printf("Cost for ...

  1. #1
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    Question help with c++

    Code:
    #include<stdio.h>
    int main()
    {
        char ans;
        int month,food,trans,eqp,misc;
        float total=0,over=0;
        do
        {
              printf("Enter your monthly allowance:");
              scanf("%d",&month);
              printf("Cost for food:");
              scanf("%d",&food);
              printf("Cost for transportation:");
              scanf("%d",&trans);
              printf("Cost for equipment:");
              scanf("%d",&eqp);
              printf("Other miscellaneous:");
              scanf("%d",&misc);
              total=food+trans+eqp+misc;
              printf("Total cost is RM%0.2f\n",total);
              if(total<month)
               printf("Alhamdulillah!");
              else
               over=total-month;
               printf("You exceeded RM%0.2f in your monthly allowance\n",over);
               
               printf("Enter 'y' to continue:");
               scanf("%c",&ans);
        }while(ans=='y');
        printf("Good bye.\n");
        
        system("pause");
        return 0;
    }
    what is wrong with this progm?

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    The big answer is "it's C, not C++".

    Other reasons are: it is -- well, not impossible, but very difficult -- for your do-while loop to loop more than once. (You would have to type the 'y' for continuing at the end of your Other miscellaneous input, since otherwise the \n character will be in the way.) If you want to make sure the input character is not whitespace (space bar, enter key, etc.) then you need to use " %c" in your scanf call.

    Other other reasons: You have to be on a OS where "pause" is a valid command to the operating system, which many people are not.

  3. #3
    Registered User whiteflags's Avatar
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    Also, I am sure that these were unintentional oversights:
    Code:
              if(total<month) {
               printf("Alhamdulillah!");
              } else {
               over=total-month;
               printf("You exceeded RM%0.2f in your monthly allowance\n",over);
              }

  4. #4
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    Compare your program to mine, and any differences are 'wrong'.

    Code:
    #include <stdio.h>
    #include <iostream>
    #include <string>
    
    using namespace std;
    
    int main()
    {
        string _last;
        float _allowance, _food, _trans, _eqp, _misc;
        float total = 0;
    
    	cout << "Enter your monthly allowance: $";
    	cin >> _allowance;
    	cout << "Cost for food: $";
    	cin >> _food;
            cout << "Cost for transportation: $";
            cin >> _trans;
            cout << "Cost for equipment: $";
            cin >> _eqp;
            cout << "Other miscellaneous costs: $";
            cin >> _misc;
            total = _food + _trans + _eqp + _misc;
            cout << "\nTotal cost is $" << total << endl;
            
              if(total < _allowance)
                      {
    			cout << "Alhamdulillah!" << endl;
    		  }
              else if(total > _allowance)
                      {
                             cout << "You exceeded your monthly allowance! \n";
    		  }
              
             cout << "Enter \"again\" to run the program again, and press Enter to exit. \n"; 
             cin >> _last; 
             
             if(_last == "again") //Re-Execute the program if you wish.
             {
    			 main();
             }
    	else //If not, exit the program
    	{
    			 return 0;
    	 }
    
    }

  5. #5
    Registered User NeonBlack's Avatar
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    Quote Originally Posted by User-_-Name View Post
    Compare your program to mine, and any differences are 'wrong'.

    Code:
             if(_last == "again") //Re-Execute the program if you wish.
             {
    			 main();
             }
    	else //If not, exit the program
    	{
    			 return 0;
    	 }
    Well that's got to be one of the wrongest things I've ever seen.
    I copied it from the last program in which I passed a parameter, which would have been pre-1989 I guess. - esbo

  6. #6
    and the hat of wrongness Salem's Avatar
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    > float _allowance, _food, _trans, _eqp, _misc;
    You should also know that identifiers beginning with underscores are reserved.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  7. #7
    C++まいる!Cをこわせ! Elysia's Avatar
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    Quote Originally Posted by Salem View Post
    > float _allowance, _food, _trans, _eqp, _misc;
    You should also know that identifiers beginning with underscores are reserved.
    To be pedantic, it's names that begin with an underscore + An uppercase letter. Or names that begins with two or more underscore identifiers. So it's actually safe in scopes inside functions (not global scope).

    Also, stdio.h should be cstdio. But then again, is it even used?

    Furthermore, remember that main shall not recursively call itself. Use a loop.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

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