C++ :: Read Function - Compare And Assign Variables
Mar 1, 2013
I am developing a program that will read a function (x^2+2x+4 or other function) and then comparing and start assigning variables. My idea is with an array:
int i,x;
char xs;
char function[20];
cin.getline(function, 20);
cout << "Your function is: ";
[Code] .....
Well this is my basically idea, but when the program detect an ^ this will be associate with the exp(x,n); well in general the user enter a function: x^3+3x^2+4x-8 give a value for x for example 3 and the program will convert in -- exp(3,3)+3*exp(3,2)+4*3-8 --, but I don't know how.
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Oct 29, 2014
I try to use passing function as argument but I'm stuck. I have two questions: First, I try to call uppercase and open .txt in tfm Second, How can I read characters from in.txt as string and assign to char content[] ?
#include <stdio.h>
void tfm( char str_filename[], void(*pf_convertion)( char content[]));
void uppercase(char content[]); //converts all letters to uppercase
int main(){
puts("-------------------------------");
printf("tfm:
");
tfm("in.txt", uppercase);
[Code] ....
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Feb 3, 2013
How do I compare two variables who do not have a predefined Type (i.e Templates).
If I just do a==b it only works for integers and not for strings. Is there any general method present for comparing templates.
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Mar 5, 2014
I'm trying to read a string and then compare it to a word.
My code:
char* cmd = "start";
std::cin >> cmd;
if (strcmp (cmd, "eval"))
eval ();
When the program gets to the cin part, it breaks.
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Jul 6, 2014
I'm trying to compare prices which are read from the file along with other information. The input file is as shown below: The file data is something like this:
//Program to test the class listType
#include <iostream>
#include <fstream>
[Code]....
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Apr 19, 2013
I have a list of objects that I need to read information from each object to compare to a user input prompt.
#include "Passenger.h"
#include "Reservation.h"
#include "Aircraft.h"
#include <iostream>
#include <fstream>
#include <string>
#include <list>
using namespace std;
//Function Prototypes
void flightRoster(list<Reservation>&);
[Code] ....
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Jan 24, 2013
How can we assign a pointer to a function? const char* function_name(), here what exactly does the pointer point to?
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May 26, 2013
Im starting with C. Like I said in the title, how do I assign the value from a function to a variable? I mean I have this function:
Code:
int EnteroAleatorio(){
rand();
return rand();
}
and I would like to assign the value of EnteroAleatorio to a variable in my main function, but when I try to do it and compile, I got the next error: non-lvalue in assignment
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May 12, 2013
I want my program to read variables from file "input.txt":
Please choose the crystal lattice. Type 1 for BCC, 2 for FCC, and 3 for HCP: 2
Please enter lattice parameter (a): 1
For HCP please enter second lattice parameter (c): 1
Please enter the number of translated cells along X axis: 2
Please enter the number of translated cells along Y axis: 2
Please enter the number of translated cells along Z axis: 2
Moreover, I want program to read only the numbers after colon. How can I do it?
Code:
#include <iostream>#include <fstream> // to read from file
using namespace std;
int main () {
int latticeType;
int dimX, dimY, dimZ; // number of translated cells along each axis
float d; // lattice parameter
[Code] ....
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Dec 9, 2013
I am trying to fscanf a file and need to read the variable name 'f9' and 'a2' for example in the sample below and get their corresponding values '8' and '2' and then in my C program set the variables f9 and a2 accordingly (which I can declare as variables). Is this possible?
I making a Sudoku Solver and am thinking I would store the puzzle solution in a 2D array with a1=0, a2=1, etc... where 0, 1 are the array indices... then just print the array as the solution.
Note: The a1, a2, a3, etc... is my own numbering of the indices where the letter corresponds to the row and the number corresponds to the column (starting from 1) which I use when feeding to the solver.
I have a file that has the following format (output of Z3 SMT solver):
sat
(model
(define-fun f9 () Int
8)
(define-fun a2 () Int
2)
(define-fun c5 () Int
6)
)
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Jan 16, 2013
i want to write a program that can access to variables and methods of another program. I ques for access to variables need to read memory, but about methods?how i can use methods and call them?
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May 6, 2013
So I have this text file that I am trying to read from and store the values of each line in multiple variables. Let's say my text file contains
AXSYZ3482 Tom 100 112 and my code below here works fine when the lines in the text file is separated by spaces.
Code:
while (fscanf(fp, "%s %s %d %d
", userID, name, &startLoc, &endLoc) != EOF) {
printf("%s %s %d %d
", userID, name, startLoc, endLoc);
}
But let's say my file was to look like this instead.
AXSYZ3482:Tom:100:112
But if i try this below...
Code:
while (fscanf(fp, "%s:%s:%d:%d
", userID, name, &startLoc, &endLoc) != EOF) {
printf("%s %s %d %d
", userID, name, startLoc, endLoc);
}
It seem to store the entire line in userID including the ":". I want to ignore the ":"'s and store everything in between in respective varibles in the order specified above.
So first string in userID, then ignore the :, then second string in name, and ignore the next :, and so forth.
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Dec 8, 2014
So I have to read from a file, and store the information in separate variables. My problem is that for some of the information I need multiple words, and for others I don't, so I cant simply store 1 word into a variable and store the next in another in so on. To demonstrate what I mean let me give an example.
Dog Cat Blue Bird Snake White Horse
I am able to store "Dog","Cat","Blue","Bird"...etc in variables but I don't know how to make it so I can store "Dog" in one variable, "Cat" in a second variable. and "Blue Bird" in a third variable. "Snake" would be the 4th and "White Horse" would be the fifth. How can I read a file and manipulate the pointer to grab what I need?
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Oct 18, 2014
How can I declare a set of strings that i want to be ordered by a boolean function Comp? Like the one you would write in
sort(v.begin(), v.end(), comp);
I tried
set<string, Comp> S;
but it doesn't work
And the same question for priority queues, can you specify the function you want your elements to be sorted by?
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Feb 10, 2015
I have an assignment in my OOP c++ class and I had to create a class called date and one of the member functions is a compare function that compares two dates that are taken in. It is suppose to be something like this:
Date d1(12,25,2003);// Dec 25, 2003
Date d2(5,18,2002);// May 18, 2002
d1.Compare(d2);// returns 1 (since d2 comes first)
d2.Compare(d1);// returns -1 (calling object is d2, comes first)
Then if d1 and d2 are equal then it returns 0.
This is what he gave us to start with the function:
int Date::Compare(const Date& d) {
}
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Sep 30, 2013
I am a newbie to C++ and VS ++. I have created a windows form application by dragging and dropping button, label..etc. i wish label text to be appeared as return value from a function. The function returns ' const char* '.how this returned string pointer can be used to display label text.?
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Sep 7, 2013
I was wondering about the function strcmp(), does the function compare word with spaces? eg: If I have two same words "Harith Javed"; will it match both words??
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Aug 22, 2013
I can't get my code to compile, i need to read in lines from a file and store them in variables. Then i have to construct instances of my class for how many lines there are in the file and take those variables into them.
I'm getting this error :
"a2.cpp:40: error: cannot convert `Employee' to `Employee*' in assignment"
#include<iostream>
#include<string>
#include<fstream>
void displayInfo();
using namespace std;
class Employee{
[Code] .....
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Mar 26, 2014
I am trying to bend my head around polymorphism but I can't figure out how to use the virtual method properly. I have the following superclass:
Code: class comparable
{
public:
comparable();
virtual bool compare(comparable &other)=0;
}; and the subclass:
Code: class score : public comparable
{
public:
score(string player,int highscore);
bool compare(comparable &other);
string name;
int highscore;
};
My problem is that I do not know how to define the virtual function compare in the subclass score:
Code: bool score::compare(comparable &other){
if(this->highscore > other.???){
...
}
}
How do I tell the compiler that the type is of score?
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Feb 18, 2013
Modify your code by adding your own tests to see if your functions work right. Include at least 6 separate tests, of your choosing.
For example, test the compare function with the first parameter as a blank string -- then with the 2nd as a blank -- then both. Test compare with the first string shorter than the second -- then the other way around. Test your copy function with long strings.
I am struggling with how to use the compare function with a parameter as a blank string. I tried leaving the first parameter blank but doing ("",text) but I don't think that is the correct way of doing this.
#include <cstring>
#include <iostream>
using std::cin;
using std::cout;
using std::endl;
int myStrLen(const char[]); // return length of null-terminated string stored in char array
[Code] ....
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Oct 21, 2014
The question is to write a recursive boolean function that compares two stacks and returns true if they are identical. This is where I get stuck:
If the top items of both stacks are the same, the recursive call always returns true, because 'true' is saved on top of the return stack.
Here is my code:
template<class Type>
bool identicals(stackType<Type> s1, stackType<Type> s2) {
if(!s1.isEmptyStack() && !s2.isEmptyStack()) {
if(s1.top() != s2.top())
[Code] ....
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Dec 8, 2013
Is possible read text form keyboard using read() function? or which is best way in ansi creplace input command form basic language. for numbers and text...
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Mar 29, 2014
ok I have a class Player with lots of variables and im gonna call a function to checkXp, if I call it with the whole player object does it use a lot more memory then if I just passed the couple things I need?
ex
checkXP(Player* play) // this is a whole object of player
or
checkXP(play->getXP(), play->getLVL()) // the variables I want.
I just realized I may not be able to modify anything from player in the checkXP() function
question 1: does passing the whole object use more memory
question 2: if I passed as just the variables I need, I wont be able to modify anything of object play?
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Jan 24, 2015
In my program I created three separate return functions. Each function is labeled:
int boxes(int x, int y);
int leftOver(int x, int y);
double avgItemsShipped(int x, int y, int z);
Is it bad programming practice to use 'x' and 'y' in all of my functions? Should I use the this keyword inside the function? We use this often in my Java class and I know it exists in C++, but I haven't actually seen it used (or used it myself yet).
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Nov 12, 2012
This is a c program that is failing to compile. The error occurs in the calcLabs() function. The error called out is (btw, I'm using VS 2010): Error4error C2143: syntax error : missing ';' before 'type'
I don't understand why the compiler is not letting me declare variables in the calcLabs() function!
Code:
#include<stdio.h>
#include<stdlib.h>
void calcPercent(double *);
double calcLabs();
double calcExams();
double calcFinal();
char calcLetter(float);
[code]...
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Mar 26, 2013
The following function uses reference variables as parameters. Rewrite the function so it uses pointers instead of reference variables, and then demonstrate the function in a complete program.
int doSomething(int &x, int &y)
{
int temp =x;
x = y * 10;
y = temp * 10;
return x + y;
}
I understand how to covert the reference variables to pointers, however I am stuck on this error. Either I get the error listed in the title or (with a few changes) the error "invalid conversion from 'int' to 'int*'"
What am I doing incorrectly?
#include <iostream>
using namespace std;
int doSomething(int*, int*);
int main(){
int X, Y, result;
[Code] ....
I have multiplied both x and y by 10 and then added them together!
Here is the result " //I really didn't know how else to use the "doSomething" function in a meaningful way. So... I just stated what the function does.
<< result << ".
";
system("PAUSE");
return 0;
}
int doSomthing(int *x, int *y)
[Code] .....
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