C++ :: How To Avoid Using Backspace Character With Push Back
Mar 28, 2014
How to avoid using Backspace character with push_back? I'm making a software as an ATM, so when the user try to enter the password the user only sees *******, but when trying to delete it doesn't delete a character. It just adds a new one. Here's my code:
I am trying to use push back in a 2D vector but I don't know how to. This is what I have:
vector <vector <BigInt> > matr;
for (BigInt i=0;i<rij;i++) { for (BigInt j=0;j<kolom-1;j++) { matr.push_back().push_back((i+1)^(pow-j)); } }
I quickly invented something but that doesn't work obviously. it should be equivalent to this: (the only problem in the code below is that those indexes don't exist yet that's why I need push_back())
for (BigInt i=0;i<rij;i++) { for (BigInt j=0;j<kolom-1;j++) { matr[int(i)][int(j)]=(i+1)^(pow-j); } }
Code: class moClassValueContainer { public: moClassValueContainer(); moClassValueContainer(string,int); [Code] ....
In my main.cpp, I have blow loop
Code: for (xml_node tnode = it->first_child(); tnode ; tnode = tnode.next_sibling()) { Container tmpContainer(tnode); if (tmpContainer.getType() == SINGLE) { string t = tmpContainer.getName();
[Code] ....
I cannot push_back(t). I examined the code with debugger, t has correct string value assigned, but even after 20-30 iterations, there is no element for headerFields vector.
In the following char array, notice the use of a backspace character in a string literal: ''.
char text1[50] = "aHello, World! Mistakee was "Extra 'e'"! ";
What exactly does a backspace character do here? When the compiler evaluates this line, does it actually delete the previous character, like when you press the backspace button on the keyboard?
#include <string> #include <vector> using namespace std; class Question { string title; vector<Thing*> posAns; vector<Thing*> negAns;
[Code] ....
error: no instance of overloaded function 'std::vector::push_back()' matches the arguments list argument types are (const Thing *) object type is: std:: vector<Thing *, std::allocator<Thing *>>
So it cannot be constant, what if I just leave it non-constant? Will it be safe?
How to output vector contents using the push_back function. My program reads in values just fine, but it does not output anything and I've been stuck on why.
here is my code:
#include <iostream> #include <array> #include <vector> using namespace std; int duplicate( vector < int > &vector1, const int value, const int counter)
the code use in above link is good but one problem i cant able to use backspace to remove mistake if user made any mistake he cant able to remove the mistaken character
I have a c program that I partially have working. The problem is basically writing a program that allows the user to input the amount of calories they plan to eat a meal and disperse the calories from top to bottom. My program produces the output in the example if I enter 1050 but the issue I noticed if the number of calories is just enough to cover the burgers I get negatives in the other variables.
For example, if I enter a total amount of calories of 1050, I can eat: Output: 2 burgers @ 770 calories (1050 - 770 = 280 calories remain) 1 bag of pretzles @ 170 calories (280 - 170 = 110 calories remain) 1 pear @ 80 calories (110 - 80 = 30 calories remain) 6 tsp. ketchup @ 30 calories If I input 1050 I get the above output but if I input a different integer such as 2000 this is my output 5 burgers @ 1925 calories 0 bag of pretzles @ 0 calories -1 apple @ -80 calories -35 tsp. ketchup @ -175 calories I can't give the full code since this assignment holds a lot of points and was up all night getting it work.
So I'll provide pseudocode
define all 4 variables burger 385, pretzel 170, pear 80, ketchup 5 print out text How many calories can you eat prompt user input Divide user input into burger How many burgers can bet eaten subtract calories eaten from original user input Divide calories left into pretzel How many bags can bet eaten subtract burger calories from pretzel calories Divide calories left after preztel into pear How many pretzels can be eatn subtract pretzels calories from pear calories Divide calories left over into ketchup how much ketchup can i use show on screen (int total)of burgers @ (int calorie total) calories show on screen (int total)bags of pretzels @ (int calorie total) calories show on screen (int total)pears @ (int calorie total) calories show on screen (int total)teaspoons of ketchup @ (int calorie total) calories
The problem I see is that subtracting the calories from the pear from the left over calories of the pretzel calories leads to a negative. If leftover calories minus 80(pear int) its less then 0 . The calculations from the pear onward to ketchup become incorrect resulting in negative output.
I've been making an RPG in C++ and I've used goto all throughout the program. After receiving an error and Googling how to fix it, I read that you shouldn't use goto. What can I use as a instead of goto, which isn't 'considered bad programming practice'?
Problem:Say I have a Base class called Car and it has 3 derived classes say Ford, Honda and Audi.
now the issue is all 3 derived classes have exactly same code but minor difference in calling member functions of their r respective engines( these engines have separate class) . example ford class calls code which is exactly same as other 2 classes but do call something like ford_engine-> start() ford_engine->clean() bla bla bla .
//ly Audi calls audi_engine->start() audi->clean();
now here the issue is it has redundant code in all 3 places with minute difference. Hoow I can have code at one place most probably in Base class and all derive classes uses same code.
I have table called leavetable where in i have the fields eid, lfrom,lto, reason,status an employee will insert these fields in the leave form except status, status will be updated by admin but there is no unique field in the table so when the admin updates the status as cancel for an id emp001 so whereever this id is present in the table its getting updated to cancel even though it is approved previously.. How to avoid this duplication ?
SqlConnection con = new SqlConnection(Connectionstring); con.Open(); string sql = "update leavetable set status = '"+status+"' where eid = '"+textBox1.Text+"' and noofdays = '"+textBox5.Text+"'";
I am working on a parking lot scenario project using multidimensional arrays. The parking lot has 8 rows and 10 parking spaces in each row. Altogether there are suppose to be 30 cars parking in the lot and arrive in numerical order. I am suppose to generate a random number to represent the row and another to represent the space in the row.
The problem I have is that a few of the elements are being replaced. The project requires the car to check if the space is taken, if so it is to find another one. Here is what I have...
I am developing a Visual C++ application. There is an object called CMyObject, as follows:
typedef CMap<UINT, UINT, void *, void*> CMyMap; class CMyObject { public: CMyMap *m_pMyMap; "Some other member variables" }
Some instances of CMyObject contains a map, some not. Therefore, to save memory, I define a pointer m_pMyMap and create a new CMap object only if the instance contains a map.
When I test my app, with the increase of the CMyObject instance, the number of memory blocks allocated and deallocated is also increasing. There are a lot of fragments during this period. To prevent this, I try to override the new/delete operator for CMyObject and CMyMap. But still find many fragments. So I try to trace into the MFC source codes for CMap. I find CMap is just using an internal buffer to store the hash table(m_pHashTable), as follows:
m_pHashTable = new CAssoc* [nHashSize];
And for each hash entry, it uses:
P = (CPlex *)new BYTE[sizeof(CPlex) + nMax *cbElement];
To allocate the spaces.
I believe these two may be the reason of the memory fragments and want to eliminate them. However, is there a way to override the new/delete operator for codes such as:
new CAssoc* [nHashSize] and (CPlex *)new BYTE[sizeof(CPlex) + nMax *cbElement]
So that the spaces will be allocated from my own memory manager instead of from the default heap?
I was wondering if it's possible to push a button on a website programatically. Unfortunately the button link is invisible, otherwise I could simply use the URL it links to. So is there a way to do it in c++ and if so, how?
I've been playing around with making a linked list in C and am having trouble adding to the beginning of the list. For the add_beg() function: the statement "head = newNode" only works locally. This leads me to believe this is a pointer problem. However, the add_end() function works correctly. Ideally, I would like to print "0 1 2 3 4" after using the add_end(root, 0). Currently, print only gives me "1 2 3 4".
#include <stdio.h> #include <stdlib.h> //Create a node struct typedef struct node { //data int val;
