Error indirection requires pointer operand int invalid

Error indirection requires pointer operand

I get this error when I try compiling my code is there a way I can fix this.

testings.cpp:69:48: error: indirection requires pointer operand
(‘List ::It’ invalid)
for (; begin != end; ++begin) this->Insert(*begin);
^

testings.cpp:114:12: note: in instantiation of function template specialization
‘List ::List
::It>’ requested here
List first (test.begin(), test.end());
^
testings.cpp:94:13: warning: expression result unused [-Wunused-value]
this->cur;

testings.cpp:69:26: note: in instantiation of member function
‘List ::It::operator++’ requested here
for (; begin != end; ++begin) this->Insert(*begin);
^
testings.cpp:114:12: note: in instantiation of function template specialization
‘List ::List
::It>’ requested here
List first (test.begin(), test.end());
^
1 warning and 1 error generated.

Don’t return a reference, just return It.

You haven’t defined operator!= for your iterators. (Although you might find that setting your end iterators internal pointer to «fin» is not going to work too well.)

Your Size method actually counts the nodes in the list, even though you have a size member that you could return (as long as you update it properly; for instance, RemoveFront should subtract 1 from it.).

Your default ctor has a pointless initializer_list in it.

In this function, the expression It(start) is a temporary object. The language refuses to take a (non-const lvalue) reference to it, because the referent would be destroyed immediately at the semicolon of the return statement.

You don’t want to return a reference to a temporary value at all: just return by value:

Same advice for end().

Then, your problem is that you never implemented operator overloads for List::It.
You also have never provided a suitable constructor for List::Node.

Источник

компиляция — косвенное обращение требует операнда указателя и ожидаемых ошибок выражения

Я продолжаю получать ошибки, подобные этим:

Решение

Не c++ эксперт, но я уверен, что для определения константы вам просто нужно использовать #define директива, за которой следует символ и значение, которое вы хотите присвоить ему (даже если само значение является выражением, даже если такое выражение ссылается на другую константу), фигурные скобки и конечная точка с запятой являются чрезмерными:

Составлено с первой попытки с такими исправлениями.

Другие решения

Причиной ошибки является точка с запятой в конце директивы #define.

Вы также использовали неправильный тип скобок, попробуйте вместо этого:

#define UNLEADED 3.45

#define SUPER (UNLEADED + 0.10)

#define PREMIUM (SUPER + 0.10)

Обратите внимание, что когда вы используете директиву #define, все, что следует за #define, подставляется в ваш код. В этом случае после запуска препроцессора ваш код выглядел так:

else if(gasType == «UNLEADED»)
<
cost = UNLEADED 3.45; * gallons;
>
else if(gasType == «SUPER»)
<
cost = ; * gallons;
>
else if(gasType == «PREMIUM»)
<
cost = PREMIUM ; * gallons;
>

Причина, по которой вы получили indirection requires pointer operand Ошибка была в том, что компилятор пытался интерпретировать это утверждение:

Поскольку * оператор имеет только один аргумент, он интерпретируется как разыменование указателя, к счастью для вас gallons переменная не является указателем типа. Если галлоны были объявлены типом указателя, т.е. double cost, *gallons; и cin если бы там не было, код скомпилировал бы, но не сделал бы то, что вы ожидаете, вероятно, бросив segfault.

Макросы, определенные с помощью #define, могут быть очень мощными и очень опасными. Обычно есть лучший способ добиться чего-то в c ++. В этом случае UNLEADED , SUPER_UNLEADED а также PREMIUM может быть объявлен как const double типа то есть

const double unleaded = 3.45;
const double super = unleaded + 0.10;
const double premium = super + 0.10;

Источник

Error indirection requires pointer operand

Hello guys,
i have a problem with Iterators. The exercise is to let the user input numbers in a vector. I then have to add the first and the last number, then the second and the second last number. etc. But in my for loop i get an error while i try to print the second iterator, whose job is to iterate through the vector from the back. The error message is:
Indirection requires pointer operand (‘long’ invalid)

Welcome to the forum.

It looks like the problem is in line 12, i.e., the math.

If «store.begin() = 0» and «store.end() = 10 then your formula would be » 0 + 10 — (0 / 2) or 0″ which would end up as «0 +10 — 0». Not quite the mid point you are looking for. I think what you want is: auto vectorMid = (store.begin() + (store.end()) — ((store.begin() + store.end())/2); . And yes due to the order of precedence, see http://www.cplusplus.com/doc/tutorial/operators/#precedence , All those () are necessary. Note look at level 5 and 6.

And I think I would move line 16 to line 13 and change the for loop to end with «it++, it2—)». Since the value of «store.end()» should not change and setting the value of «it2» inside would yield the same address each time.

Now I have not tested this yet. This is what I see for now. I will load it up and give it a try though.

Источник

компиляция — косвенное обращение требует операнда указателя и ожидаемых ошибок выражения

Я продолжаю получать ошибки, подобные этим:

Решение

Не c++ эксперт, но я уверен, что для определения константы вам просто нужно использовать #define директива, за которой следует символ и значение, которое вы хотите присвоить ему (даже если само значение является выражением, даже если такое выражение ссылается на другую константу), фигурные скобки и конечная точка с запятой являются чрезмерными:

Составлено с первой попытки с такими исправлениями.

Другие решения

Причиной ошибки является точка с запятой в конце директивы #define.

Вы также использовали неправильный тип скобок, попробуйте вместо этого:

#define UNLEADED 3.45

#define SUPER (UNLEADED + 0.10)

#define PREMIUM (SUPER + 0.10)

Обратите внимание, что когда вы используете директиву #define, все, что следует за #define, подставляется в ваш код. В этом случае после запуска препроцессора ваш код выглядел так:

else if(gasType == «UNLEADED»)
<
cost = UNLEADED 3.45; * gallons;
>
else if(gasType == «SUPER»)
<
cost = ; * gallons;
>
else if(gasType == «PREMIUM»)
<
cost = PREMIUM ; * gallons;
>

Причина, по которой вы получили indirection requires pointer operand Ошибка была в том, что компилятор пытался интерпретировать это утверждение:

Поскольку * оператор имеет только один аргумент, он интерпретируется как разыменование указателя, к счастью для вас gallons переменная не является указателем типа. Если галлоны были объявлены типом указателя, т.е. double cost, *gallons; и cin если бы там не было, код скомпилировал бы, но не сделал бы то, что вы ожидаете, вероятно, бросив segfault.

Макросы, определенные с помощью #define, могут быть очень мощными и очень опасными. Обычно есть лучший способ добиться чего-то в c ++. В этом случае UNLEADED , SUPER_UNLEADED а также PREMIUM может быть объявлен как const double типа то есть

const double unleaded = 3.45;
const double super = unleaded + 0.10;
const double premium = super + 0.10;

Источник

Build fails: error: indirection requires pointer operand (‘void’ invalid), etc #401

parser.tab.cpp:97:10: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.filename(Rhs[1].filename());

^ parser.tab.cpp:5176:19: error: indirection requires pointer operand (‘void’ invalid) YYLLOC_DEFAULT (*yylsp, yyerror_range, 2);

parser.tab.cpp:97:3: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.filename(Rhs[1].filename()); ^

parser.tab.cpp:5176:3: error: member reference type ‘MiniZinc::ParserLocation *’ is a pointer; did you mean to use ‘->’? YYLLOC_DEFAULT (*yylsp, yyerror_range, 2); ^

parser.tab.cpp:98:10: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.first_line(Rhs[1].first_line());

^ parser.tab.cpp:5176:19: error: indirection requires pointer operand (‘void’ invalid) YYLLOC_DEFAULT (*yylsp, yyerror_range, 2);

parser.tab.cpp:98:3: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.first_line(Rhs[1].first_line()); ^

parser.tab.cpp:5176:3: error: member reference type ‘MiniZinc::ParserLocation *’ is a pointer; did you mean to use ‘->’? YYLLOC_DEFAULT (*yylsp, yyerror_range, 2); ^

parser.tab.cpp:99:10: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.first_column(Rhs[1].first_column());

^ parser.tab.cpp:5176:19: error: indirection requires pointer operand (‘void’ invalid) YYLLOC_DEFAULT (*yylsp, yyerror_range, 2);

parser.tab.cpp:99:3: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.first_column(Rhs[1].first_column()); ^

parser.tab.cpp:5176:3: error: member reference type ‘MiniZinc::ParserLocation *’ is a pointer; did you mean to use ‘->’? YYLLOC_DEFAULT (*yylsp, yyerror_range, 2); ^

parser.tab.cpp:100:10: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.last_line(Rhs[N].last_line());

^ parser.tab.cpp:5176:19: error: indirection requires pointer operand (‘void’ invalid) YYLLOC_DEFAULT (*yylsp, yyerror_range, 2);

parser.tab.cpp:100:3: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.last_line(Rhs[N].last_line()); ^

parser.tab.cpp:5176:3: error: member reference type ‘MiniZinc::ParserLocation *’ is a pointer; did you mean to use ‘->’? YYLLOC_DEFAULT (*yylsp, yyerror_range, 2); ^

parser.tab.cpp:101:10: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.last_column(Rhs[N].last_column());

^ parser.tab.cpp:5176:19: error: indirection requires pointer operand (‘void’ invalid) YYLLOC_DEFAULT (*yylsp, yyerror_range, 2);

parser.tab.cpp:101:3: note: expanded from macro ‘YYLLOC_DEFAULT’ Current.last_column(Rhs[N].last_column()); ^

10 errors generated.»>

FreeBSD 12.1
bison-3.6.4
clang-9

The text was updated successfully, but these errors were encountered:

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Problem with Iterators

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  int main()
{
    
    int input;
    std::vector<int> store;
    
    while(std::cin >> input)
    {
        store.push_back(input);
    }
    
    auto vectorMid = store.begin() + (store.end() - store.begin())/2;
    
    for(auto it = store.begin(); it != vectorMid; it++)
    {
        auto it2 = store.end() - 1 - it;
        
        std::cout << *it2 << std::endl;
        //Error: Indirection requires pointer operand ('long' invalid)
    }
    
	return 0;
}

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int main()
{
    int q = 45;
    int p = q; //Missing "pointer syntax"

    std::cout << *p << std::endl;
    //Error:Indirection requires pointer operand ('int' invalid)
    return 0;
}

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int main()
{
    int input;
    std::vector<int> store;
    
    while(std::cin >> input)
    {        store.push_back(input);
    }
    
    auto vectorMid = store.begin() + (store.end() - store.begin())/2;
    
    for(auto it = store.begin(); it != vectorMid; it++)
    {
        auto difference = it - store.begin(); //Calculate position of the first Iterator
        auto it2 = store.end() - difference - 1; //Initialize second iterator (-1 because .end() is one off the end!)
        
        std::cout << *it + *it2 << std::endl;
    }
    
	return 0;
}

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#include <iostream>
#include <vector>

int main()
{
    int input;
    std::vector<int> store;
    
    int total;
    std::cout << "How many numbers would you like to enter? ";
    std::cin >> total;
    std::cout << "Please enter " << total << " space-separated numbers: ";
    for (int x=1; x<=total; ++x)
    {
        std::cin >> input;
        store.push_back(input);
    }
    std::cout << std::endl << std::endl;
    
    auto vectorMid = store.begin() + (store.end() - store.begin())/2;
    
    for(auto it = store.begin(); it != vectorMid; it++)
    {
        auto difference = it - store.begin(); //Calculate position of the first Iterator
        auto it2 = store.end() - difference - 1; //Initialize second iterator (-1 because .end() is one off the end!)
        
        std::cout << *it + *it2 << std::endl;
    }
    
	return 0;
}

How many numbers would you like to enter?  3
Please enter 3 space-separated numbers:  10 20 30


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auto it = store.begin();
auto it2 = store.end() - 1;
for(; it<it2; ++it,--it2)
{
    std::cout << *it + *it2 << std::endl;
}
if (it == it2) // Odd number of elements
    std::cout << *it << std::endl;

Topic archived. No new replies allowed.

pitstop.cpp:36:23: error: indirection requires pointer operand

('double' invalid)

cost = UNLEADED * gallons;

^ ~~~~~~~

pitstop.cpp:40:14: error: expected expression

cost = SUPER * gallons;                               ^

#include <iostream>
#include <iomanip>
using namespace std;

#define UNLEADED 3.45;
#define SUPER {UNLEADED + 0.10};
#define PREMIUM {SUPER + 0.10};

/*
Author: Zach Stow
Date:
Homework
Objective:
*/

double cost, gallons;
string gasType, finish, stop;

int main()
{
for(;;)

{

cout <<"Hi, welcome to Pitstop.n";
cout <<"Enter the type of gas you need:";
cin >> gasType;
cout << endl;

cout <<"Enter the amount of gallons you need:";
cin >> gallons;
cout << endl;

if(gasType == "finish" || gasType == "stop")break;

else if(gasType == "UNLEADED")
{
cost = UNLEADED * gallons;
}
else if(gasType == "SUPER")
{
cost = SUPER * gallons;
}
else if(gasType == "PREMIUM")
{
cost = PREMIUM * gallons;
}

}
cout <<"You need to pay:$" << cost << endl;

return(0);

}

Решение

// [...]

#define UNLEADED 3.45
#define SUPER (UNLEADED + 0.10)
#define PREMIUM (SUPER + 0.10)

//[...]

Другие решения

The Indirection requires pointer operand error message is shown on the screen when the programmer has created a pointer to a variable by using *my_var instead of &my_var.

This article will provide detailed knowledge of this error and ways to solve it. First, let’s start with the reasons that cause this issue and find the best solutions.

The Indirection requires pointer operand error message occurs while programming because the compiler interpreted the indirect pointer operand. Some of the other reasons include syntax errors or compiling errors along with cannot take the address of an rvalue of type ‘byte’.

Other common reasons behind this situation involve:

• Using the wrong function
• Compiling error
• Wrong usage of the Buffer function
• Dereferencing the wrong array value

– Error in Syntax

Syntax errors are common while typing large programs. Syntax errors can include writing the wrong functions or using operations that create an undefined behavior. If the programmer is taking the address of a temporary object of type (any), and it is not defined, then during execution, an error will occur.

Moreover, if the programmer wants to create a pointer to their variable by using *my_var instead of &my_var, a syntax error will occur along with the pointer operand error message.

– Cannot Take the Address of an Rvalue of Type ‘Byte’

When the program cannot take the address of an rvalue of type ‘byte’, it shows a pointer error. It occurs when the conditional expression does not produce an lvalue. Following is an example for better understanding:

For Example:

– Using the Wrong Function

When a wrong function is used, just like a syntax error, it also shows an operand error in the program. In the below example, the atoi function returns an int, not int *.

Thus, there is no need to dereference the return value again. The compiler will show an error message if the programmer tries to dereference int. Here’s an example:

For example:

The error in here is “virtualAddress = *atoi(argv[2]);”.

– Compiling Error

When the compiler interprets the program as an indirect operation of a pointer, it means the compiler is an incompatible pointer to integer conversion, and so, the error occurs during execution.

In other words, if the compiler and pointer are incompatible, a pointer error will occur. Let’s explain this using an example.

Program Example:

Explanation:

In this example, the programmer has used owned operators of a pointer to a variable of integer type. Thus, the compiler interprets this as an indirect operation of a pointer.

Moreover, the function (long long * FindLength) declares a pointer to an integer of type long long, but since a compiling error occurred, the program will instead show an error message.

– Wrong Usage of the Buffer Function

Understanding the buffer function is important because the wrong usage of it can cause errors such as pointer issues in the program. Some programmers confuse between buffer and &buffer[0].

The programmer should use the buffer as an argument instead of &buffer[0]. Passing an array has the same procedure as passing a pointer to its first element or passing pointers to functions.

In the example below, the programmer has used the wrong buffer function in their array. The &buffer[0] causes a pointer operand error message to occur.

For example:

– Dereferencing the Wrong Array Value

When the programmer uses arr[n] within the function, it gives them the nth value in that array instead of giving a pointer. Therefore, if the user is trying to dereference that value (*arr[n]), it will not work unless they use an array of pointers with it.

How To Resolve the Indirection Requires Pointer Operand Error?

To resolve the Indirection requires pointer operand error message, the programmer has to pass their pointers from the functions or use correct, defined, and direct pointers and commands. Furthermore, this error can be fixed by solving the cannot take the address of an Rvalue of a type byte error.

Let’s see all the possible reasons that can solve this error. They are explained below in detail.

– Correct the Syntax Errors

Using the correct functions will eliminate syntax errors and get rid of error messages related to pointers. There are various software that help in detecting these errors and help the user to correct them.

Let’s take an example: the programmer is dereferencing a long program and needs it in an unsigned long int. Then instead of using “atoi” in “virtualAddress = *atoi(argv[1]);”, they should use the strtoul function. Here’s an example:

Program:

– Use Vector of Pointers C++ To Resolve the Error

When the programmer uses a vector of pointers c++ to resolve the error, they have to be careful with the pointers and operands. With the help of this function, the programmer can avoid pointer errors. Vector is used as an alternative to some pointers. Here’s an example;

For example:

The output:

As you can see, the same list of alphabets is displayed twice. To elaborate, the first statement in the main() function creates six characters with their identifiers or pointers. Whereas the second statement represents these characters with their memory addresses, resulting in a vector of pointers to chars.

– Solving (Cannot Take the Address of an Rvalue of Type ‘Byte’) Error

When the rvalue of byte type is not addressed, the (cannot take the address of an rvalue of type ‘byte’) error message occurs. Due to this error, a pointer error also arises. Therefore, the programmer must use the correct commands to remove this error.

Let’s see the correct commands from the example above.

Program

– Pass Pointer to Function C++: Compilation

As mentioned above, the user cannot apply the owned operators of a pointer to a variable of integer type. If they do that, the compiler will show an error because it will interpret the program as an indirect pointer operation.

Therefore, to remove this error, the programmer has to correct the syntax error and pass pointer to function C++. This means the pointer has to pass from the function for the compiler to interpret it correctly. However, this is suitable if the user is using C++ language. Let’s take an example.

Wrong program:

Conclusion

After reading this article completely, the reader will have maximum knowledge about this error and they will be able to resolve it using the different methods shown in this article. Some important points to keep in mind are:

• The pointer should define the operator. Otherwise, the error will occur.
• No usage of pointers can cause the same error to occur.
• While creating the pointers that will support the variables in the program, make sure to use the right functions.

The reader can now proceed to resolve similar programming errors by the guidance provided in this article. Thank you for reading!

Reference

• https://cs50.stackexchange.com/questions/30016/pset1-error-indirection-requires-pointer-operand
• https://stackoverflow.com/questions/38237355/error-indirection-requires-pointer-operand-int-invalid
• https://www.reddit.com/r/cs50/comments/4c7gn4/passing_pointers_to_functions_error_indirection/
• https://github.com/vlang/v/issues/3336
• https://linuxhint.com/cpp-vector-pointers-examples/#2