lvale problem in function definition/

This is a discussion on lvale problem in function definition/ within the C++ Programming forums, part of the General Programming Boards category; Code: #include<iostream> #include<conio.h> void perfect(int); // function prototype using std::cout; using std::cin; using std::endl; int main() { int num; // ...

  1. #1
    o0o
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    lvale problem in function definition/

    Code:
    #include<iostream>
    #include<conio.h>
    
    void perfect(int);  // function prototype
    
    using std::cout;
    using std::cin;
    using std::endl;
    
    int main()
    {
        int num;    // declare varibale
        
        cout<< "Enter an integer:\t";   // prompt the user for input
        cin>> num;  // read num
        
        perfect(num);
    
    getch();
    }
    
    // definition perfect()
    
    void perfect(int userChoice)
    {
        int sum,rem;
        
        for(int value=1;value<=userChoice;value++)
        
        rem=userChoice/value;
        sum+=value;
        int result=1+sum;
        
        if((userChoice/value)==0 && result=userChoice)
            cout<< "perfect";
        else
            cout<< "not perfect";
    }
    4 erors in this program. It is supposed to tell wether a number is perfect number or not.
    int sum,rem;

    for(int value=1;value<=userChoice;value++)

    rem=userChoice/value;
    sum+=value;
    int result=1+sum;

    if((userChoice/value)==0 && result=userChoice)
    cout<< "perfect";
    else
    cout<< "not perfect";
    The user inputs 'userChoice'. userChoice is divided by the 'value'. After that it sums up all the value and if result is equal to the num it couts' perfect, yet some logical errors in the program.

  2. #2
    Skunkmeister Stoned_Coder's Avatar
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    Code:
     if((userChoice/value)==0 && result=userChoice)
    I think u meant...
    Code:
     if((userChoice/value)==0 && result==userChoice)
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

  3. #3
    o0o
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    okeys it reduces to 3 errors if i do so but the compiler gives this error now
    :...:' in function void perfect(int).

    &

    :39: name
    lookup of `value' changed for new ISO `for' scoping

    sum+=value;
    compiler highlights the above.

  4. #4
    Skunkmeister Stoned_Coder's Avatar
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    only other real problem i can see is sum is uninitialised at first use and you ought to return 0 at end of main out of courtesy especially as not all compilers may support the implicit return 0. Oh and sorry this should have been correct line...
    Code:
    if(userChoice/value==0 && result==userChoice)
    Last edited by Stoned_Coder; 01-14-2004 at 07:00 AM.
    Free the weed!! Class B to class C is not good enough!!
    And the FAQ is here :- http://faq.cprogramming.com/cgi-bin/smartfaq.cgi

  5. #5
    o0o
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    Ofcourse '==' is 100% right. I am using a DEV-C++ compiler and it gives 3 errors for the following code;

    Code:
    #include<iostream>
    #include<conio.h>
    
    void perfect(int);  // function prototype
    
    using std::cout;
    using std::cin;
    using std::endl;
    
    int main()
    {
        int num;    // declare varibale
        
        cout<< "Enter an integer:\t";   // prompt the user for input
        cin>> num;  // read num
        
        perfect(num);
    
    getch();
    }
    
    // definition perfect()
    
    void perfect(int userChoice)
    {
        int sum,rem;
        
        for(int value=1;value<=userChoice;value++)
        
        rem=userChoice/value;
        sum+=value;
        int result=1+sum;
        
        if((userChoice/value)==0 && result==userChoice){
            cout<< "perfect";}
        else
            cout<< "not perfect";
    }

  6. #6
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    Do you need brackets for you for loop?

    or is it only supposed to loop next line?

  7. #7
    o0o
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    brackets?

    whats the logic behind brackets??

  8. #8
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    your for loop will only loop through the following statement without brackets
    Code:
    for ()
    statement;
    
    so you need brackets
    for ()
    {
     statement1;
     statement2;
    }
    
    this will loop the two statements instead of just the first

  9. #9
    o0o
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    okeys thanku. I'll keep that in mind.

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