I receive the errors:
cs163hw1.cpp:41:24: error: no ‘int menutype::run_prog()’ member function declared in class ‘menutype’
and
main.cpp:18:7: error: ‘struct menutype’ has no member named ‘run_prog’
When attempting to compile my program with the associated code (spanning the appriprait .cpp and .h files):
int main(int argc, char ** argv){
...
menu.run_prog();
...
class menutype{
public:
menutype(int);
int display();
int run_prog();
private:
extras list;
person menup;
};
int menutype::run_prog(){
bool exit = false;
int input;
while(!exit){
input = 0;
while(input < 1 || input > 4)
input = display();
switch(input){
case 1 :
break;
case 2 :
break;
case 3 :
break;
case 4 : exit = true;
break;
default :
break;
}
}
}
I have no idea why this is happening, any guesses?
You need to have the class menutype declared above main(). Better still is to move the class to its own dedicated file called menutype.cpp and include the header in main's source file. As you have described it, the complier has no knowledge of menutype yet as its parsing the source file from the top of the file.
Related
While compile the below code got compilation error as
rise.h: error: pointer to incomplete class type is not allowed (fall->value = id)
While I added the function definition in dot cpp file, got linking error.
Note: Its working fine without inline.
File: fall.h
#include<rise.h>
class Fall
{
public:
char value;
};
File: rise.h
#include<fall.h>
class Fall;
class Rise
{
public:
Fall *fall;
inline void fill_the_val(struct ring *buf, char flag=false, char id = 0)
{
if(true == flag)
{
fall->value = id; //this line got compilation issue
}
}
};
File: rise.cpp
#include<fall.h>
#include<rise.h>
int main()
{
fill_the_val(buf, true, 1);
}
I'm writing a c++ stack and queue implementation program, I finished the stack part, but when compiling I'm getting these errors
arrayListImp.cpp:18:19: error: expected unqualified-id
arrayList[++top]= x;
^
arrayListImp.cpp:28:13: error: 'arrayList' does not refer to a value
itemPoped=arrayList[top];
^
./arrayList.h:3:7: note: declared here
class arrayList{
^
arrayListImp.cpp:35:9: error: 'arrayList' does not refer to a value
return arrayList[top];
^
./arrayList.h:3:7: note: declared here
class arrayList{
^
arrayListImp.cpp:46:9: error: 'arrayList' does not refer to a value
cout<<arrayList[i]<<endl;
^
./arrayList.h:3:7: note: declared here
class arrayList{
^
4 errors generated.
Here is the header file
#ifndef ARRAYLIST_H
class arrayList{
public:
arrayList();
static const int maxSize = 10;
int array[10];
};
class stack : public arrayList{
public:
stack();
void push(int x);
void pop();
int Top();
int isEmpty();
void print();
int x;
int top;
int itemPoped;
int i;
};
#define ARRAYLIST_H
#endif
arrayListImp.cpp
#include <iostream>
#include "arrayList.h"
using namespace std;
//Stack implementation
stack::stack(){
top = -1;
}
void stack::push(int x){
if (top == maxSize -1){
cout<<"Stack overflow"<<endl;
}
else{
arrayList[++top]= x;
cout<<x<<", is pushed on to the stack"<<endl;
}
}
void stack::pop(){
if (top == -1){
cout<<"Stack underflow"<<endl;
}
else{
itemPoped=arrayList[top];
top--;
cout<<itemPoped<<", is poped from the stack"<<endl;
}
}
int stack::Top(){
return arrayList[top];
}
int stack::isEmpty(){
if (top == -1) return 1;
return 0;
}
void stack::print(){
cout<<"Stack: "<<endl;
for (i = 0; i<=top; i++){
cout<<arrayList[i]<<endl;
}
}
arrayListUse.cpp
#include <iostream>
#include "arrayList.h"
using namespace std;
int main()
{
//Stack testing
stack S;
S.push(1);S.print();
S.push(2);S.print();
S.push(3);S.print();
S.pop();S.print();
S.push(4);S.print();
//Queue testing
return 0;
}
Can you please point out to what I'm doing wrong here?
You should just read your error messages.
You should use array instead of arrayList, which is the name of the class. So just refer to the variable instead.
The error message you got is something like
test.cpp: In member function ‘void stack::push(int)’:
test.cpp:44:18: error: expected unqualified-id before ‘[’ token
arrayList[++top]= x;
^
When you check the line, you immediately see what is wrong there.
You declare a constructor arrayList::arrayList(), but you do not define it. Either you can drop the declaration, or you should implement it in the cpp-file.
arrayList::arrayList() {
// do some initialization
}
The error message you got is something like
/tmp/cc4y06YN.o:test.cpp:function stack::stack(): error: undefined reference to 'arrayList::arrayList()'
The code could compile, but it did not link. So all declarations may be correct, but a symbol was missing. This is usually the case when you declared something you referred to, but you never defined it.
You always have written
arrayList[...]
what is the name of your class but reading the code it seems like you wanted to write
array[...]
which would access the data.
I came across this question in an online test that I was taking. The task is to alter this program to get rid of compilation errors.
#include<iostream>
#include<iomanip>
class Vehicle
{
public:
static Car* createCar()
{
return new Car;
}
class Car
{
public:
string name;
};
private:
int seats;
};
void useVehicle()
{
Vehicle::Car *c = Vehicle::createCar();
c->name = "BMW";
}
int main(int argc, char *argv[])
{
useVehicle();
return 0;
}
The compilations errors are like:
error: ‘Car’ does not name a type
error: ‘string’ does not name a type
In function void useVehicle():
error: ‘createCar’ is not a member of ‘Vehicle’
How do I get it right ? I tried few things but could not resolve these errors.
error: ‘Car’ does not name a type
At the point of
static Car* createCar()
Car is not yet known. Move the definition of class Car above the function
error: ‘string’ does not name a type In function ‘void useVehicle()’:
#include <string>
also use std:: to qualify string
error: ‘createCar’ is not a member of ‘Vehicle’
This error will disappear once you fix the other two issues. The compiler wasn't able to parse the function declaration because it didn't know what its return type was.
Here is my code:
// WorkDamnit.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
class Scheduler
{
public:
typedef void (*function_ptr) (void);
struct Task
{
function_ptr function;
int numOfTasks;
};
void Init(Task *tasks, int numOfTasks);
private:
int _numOfTasks;
Task *_tasks;
};
void Scheduler::Init(Scheduler::Task *tasks, int numOfTasks)
{
_tasks = tasks;
_numOfTasks = numOfTasks;
}
void count() {};
Scheduler::Task task_list =
{
count, 1
};
Scheduler scheduler;
Scheduler.Init(Scheduler::Task &task_list,1);
int _tmain(int argc, _TCHAR* argv[])
{
return 0;
}
I get the following errors from the compiler:
1>c:\users\evan\documents\visual studio 2012\projects\workdamnit\workdamnit\workdamnit.cpp(49): error C2143: syntax error : missing ';' before '.'
1>c:\users\evan\documents\visual studio 2012\projects\workdamnit\workdamnit\workdamnit.cpp(49): error C2059: syntax error : '.'
The compiler doesnt seem to like the line after the class object definition. When i try to call the init() member. All i can think of is that it has to do with the pointer to function reference. Maybe someone can shed some light on this for me?
You can call call functions/methods directly outside of other methods/functions.
Scheduler.Init(Scheduler::Task &task_list,1);
2 problems in this line.
The above seems to be outside of any function/method. For eg. you can put in inside main.
The line itself is not correct. So change it to
scheduler.Init(&task_list,1);
Usually you call a method on an object not a class name, except for static methods. You don't pass the parameter type while passing parameters to the method.
So the changed line in main will look like
int _tmain(int argc, _TCHAR* argv[])
{
scheduler.Init(&task_list,1);
return 0;
}
Line 49 should be:
scheduler.Init(Scheduler::Task &task_list,1); // note the lowercase 's': the object should be used, not the class
Also it should be within a function (maybe main in your case)
I'm getting this error on line 6:
error: expected unqualified-id before '{' token
I can't tell what's wrong.
#include <iostream>
using namespace std;
class WordGame;
{ // <== error is here on line 6
public:
void setWord( string word )
{
theWord = word;
}
string getWord()
{
return theWord;
}
void displayWord()
{
cout << "Your word is " << getWord() << endl;
}
private:
string theWord;
}
int main()
{
string aWord;
WordGame theGame;
cin >> aWord;
theGame.setWord(aWord);
theGame.displaymessage();
}
There should be no semicolon here:
class WordGame;
...but there should be one at the end of your class definition:
...
private:
string theWord;
}; // <-- Semicolon should be at the end of your class definition
As a side note, consider passing strings in setWord() as const references to avoid excess copying. Also, in displayWord, consider making this a const function to follow const-correctness.
void setWord(const std::string& word) {
theWord = word;
}
Get rid of the semicolon after WordGame.
You really should have discovered this problem when the class was a lot smaller. When you're writing code, you should be compiling about every time you add half a dozen lines.
Semicolon should be at the end of the class definition rather than after the name:
class WordGame
{
};
For what it's worth, I had the same problem but it wasn't because of an extra semicolon, it was because I'd forgotten a semicolon on the previous statement.
My situation was something like
mynamespace::MyObject otherObject
for (const auto& element: otherObject.myVector) {
// execute arbitrary code on element
//...
//...
}
From this code, my compiler kept telling me:
error: expected unqualified-id before for (const auto& element: otherObject.myVector) {
etc...
which I'd taken to mean I'd writtten the for loop wrong. Nope! I'd simply forgotten a ; after declaring otherObject.
For anyone with this situation: I saw this error when I accidentally used my_first_scope::my_second_scope::true in place of simply true, like this:
bool my_var = my_first_scope::my_second_scope::true;
instead of:
bool my_var = true;
This is because I had a macro which caused MY_MACRO(true) to expand into my_first_scope::my_second_scope::true, by mistake, and I was actually calling bool my_var = MY_MACRO(true);.
Here's a quick demo of this type of scoping error:
Program (you can run it online here: https://onlinegdb.com/BkhFBoqUw):
#include <iostream>
#include <cstdio>
namespace my_first_scope
{
namespace my_second_scope
{
} // namespace my_second_scope
} // namespace my_first_scope
int main()
{
printf("Hello World\n");
bool my_var = my_first_scope::my_second_scope::true;
std::cout << my_var << std::endl;
return 0;
}
Output (build error):
main.cpp: In function ‘int main()’:
main.cpp:27:52: error: expected unqualified-id before ‘true’
bool my_var = my_first_scope::my_second_scope::true;
^~~~
Notice the error: error: expected unqualified-id before ‘true’, and where the arrow under the error is pointing. Apparently the "unqualified-id" in my case is the double colon (::) scope operator I have just before true.
When I add in the macro and use it (run this new code here: https://onlinegdb.com/H1eevs58D):
#define MY_MACRO(input) my_first_scope::my_second_scope::input
...
bool my_var = MY_MACRO(true);
I get this new error instead:
main.cpp: In function ‘int main()’:
main.cpp:29:28: error: expected unqualified-id before ‘true’
bool my_var = MY_MACRO(true);
^
main.cpp:16:58: note: in definition of macro ‘MY_MACRO’
#define MY_MACRO(input) my_first_scope::my_second_scope::input
^~~~~
I got this error because I was not declaring a variable and was using it further .
Here is my code why I was getting it.
It was because I was not declaring a variable for size of my >vector.
Just replace
int n=arr.size();
Replace Here,
int sumSubarrayMins(vector<int>& arr) {
int = arr.size();
long long sum;
long long ans =0;
for(long i =0;i<n;i++){
sum =0;
long mini=INT_MAX;
for(long long j =i;j<n;j++){
mini=min(mini,arr[j]);
sum+=mini;
}
ans+=sum;
}
return ans;
}