how to check if a specific index equal to null when i try to implement it, it gives an error for example:
vector < vector <double> > v;
v[0].push_back(0);
v[0].push_back(1);
v[0].push_back(2);
v[0].push_back(3);
v[1].push_back(10);
v[1].push_back(11);
v[1].push_back(12);
v[1].push_back(13);
if(v[0][4]==NULL) {
cout<<"empty"<< endl;
}
lets say I have a pointer p_unit of type c_unit* (c_unit is an a.b.c.)
I have a function that returns a pointer to a new c_unit object:
c_unit * man_add_unit() {
c_unit * local_p_unit;
unsigned short int local_run_code;
print_man_add_menu();
local_run_code = get_a_run_code(); // this bit just gets user input
switch (local_run_code)
[code]....
I assign that to p_unit, then add it to a vector v_units:
p_unit = man_add_unit();
v_units.push_back(p_unit);
cout << "New unit added.
";
The whole program runs on a loop, and another thing the user can do is to print out data on c_unit objects pointed to by v_units. The problem is, in that function up there ^ I give the user the option to go back to main menu without creating a unit.
Since "local_p_unit" is declared but not assigned an initial value, I'm guessing the function would return a "null" pointer (which is what's hanging me up). If I just let this run with the above code, and go to print out the unit data, the program crashes.
I tried to make an if thing with p_unit == 0 but this always returns false and doesn't catch the "bad" unit that will subsequently cause a crash.
Btw, I have considered assigning a reference to a generic c_unit object to that there local_p_unit so it won't return null, then remove pointers to that object from v_units at the end of the loop.. But I know there's got to be a better way.
This is an assignment question In C++, there is no check to determine whether the array
index is out of bounds.Design a class myArray that solves the out-of-bound array index problem and allows the user to begin the array index starting at any integer, positive or negative. Every object of type myArray should be an array of type int.
Part 1 processes only int arrays. Redesign the class myArray using class templates so that the class can be used in any application that requires arrays to process data.
I don't understand the second part. should i just change the array from int to char or something?
class A; //forward defined in class B.h
class B
{
private:
[Code]....
I get error message forward Declaration of class A;
What is going on here. Is there a way I could initialize all the vectors of type B to be set to NULL in the constructor?
struct mystruct{
int n;
};
class mscope{
public:
std::vector<mystruct> mv;
[Code] .....
So I have a vector of structs and I want to traverse it, find a struct that matches a constraint and obtain a pointer to that struct. I made a function for this purpose which takes a number and an empty pointer that will store the reference. However, after function returns the pointer becomes null. What could be causing this?
I am storing info in a vector but I want to store certain info at a particular index. I am new to using vectors and am unsure about have to do this. I am aware of the insert method but am confused on how to use it to store at a particular index.
View 1 Replies View RelatedI have vector of keyframes for animation:
struct Keyframe {
float time;// time in seconds
...
};
std::vector<Keyframe> vKeys;
And every loop i accumulate delta time to animate my object:
update(float deltaTime) {
timeRunning += deltaTime;
const float animationLen = 5.0f; // 5 seconds is total length of animation
...
To calculate current Key/index into vector i use:
float currTime = std::fmod(timeRunning, animationLen);
m_currKeyFrameInx = std::size_t(vKeys.size() * currTime / animationLen);
... use index
Can this logic fail?
Before i was using this:
float currTime = std::fmod(timeRunning, animationLen);
m_currKeyFrameInx = 0u;
for (std::size_t i = vKeys.size(); --i;) {
if (vKeys[i].time < currTime) {
m_currKeyFrameInx = i;
break;
}
}
Is it possible to pass the vector index '4' to the Height() function without passing it as a parameter of the function.
Basically, I'm trying to eliminate using 4 twice... what I'd LIKE the statement below to look like is this:
gx.Cell[4].Height();
The only way I can figure out how to get it to work is like this...
class grid{
public:
class CELL{
public:
int Height(int index); //returns the height of this cell
[Code] .....
So i have this code:
if (get_brick_at(Position(row, column)) == NULL)
Where get_brick_at is defined like this:
>Brick& get_brick_at(const Position & p) {
return board[p.get_row()][p.get_column()];
}
Now, of course this does not work since the compiler cannot convert from long int to a Position. So how do i know if the return value of get_brick_at is garbage?
I also have a couple of other situations where i want to return some kind of NULL-like value under certain circumstances.
My question is: How do i handle situations like that?
Program is supposed to check for balanced parentheses which are (), {}, [] using a vector First read in the number of lines user wishes to testReturn Yes if balanced, No if unbalanced. Missing conditions to check for unbalanced parentheses Program doesn't catch left parentheses returns YesPairs wrong parentheses together, (} returns Yes, should be No Cases with incorrect output (}, (], ))), }}}, ]]], just a space or nothing entered. how I can correctly catch the cases I've missed
Code:
#include <stdio.h>
#include <stdlib.h>
#include "char_vector.h"
int main( int argc, char * argv []) {
int i, num;
char c;
scanf("%d", &num);
scanf("%c", &c);
[Code]...
I am looking at one of the functions of an exercise:
void escape(char * s, char * t) {
int i, j;
i = j = 0;
while ( t[i] ) {
/* Translate the special character, if we have one */
switch( t[i] ) {
[code]...
Notice the while loop evaluates the current value in t to true or false. When we hit the null terminator, does that get evaluated as 0 and hence evaluates as a falsy value so the while loop exits?
When you login to my site my loginservice which is done by ajax and json make a session called context.Session["Name"]. With BreakPoints it shows that everything is good and the variables are in place. However when I use Session["Name"] it comes out as null.
I will add my code at the bottem not
using System;
using System.Collections.Generic;
using System.Linq;
[Code].....
i would like to know how to replace a value with the variable that ii is equal, i mean like a=5 i want to be able to replace the number 5 by the letter a when needed in printf. ofc i want to use this for an actual purpuse and meaning what i gave was a mere example and thxx. BTW DONT jUst DROP a few lines of code that would make it work
View 5 Replies View RelatedHow i can find two equal int in array with O(n) time complexityand O(1) place complexity?
View 8 Replies View RelatedI made my own function to search if two given strings in my function are equal but the problem is if i pass two variable like hello,hello ... result is string equal but if i pass hello , hello also give me string equal because last 4 characters same to last 4 characters of hello ...
Code:
int getSimilarityOfTwoStrings(const char str1[],const char str2[]){
int str1Len = getStringLength(str1);
int str2Len = getStringLength(str2);
int i = 0;
int j = 0;
bool truefalse;
[Code] .....
I'm making a simple calculator and have done it all right where you can input everything, all the functions are there, but when i run the program it will come to displaying the result and it will always equal zero, I just need it to say 8+8 = 16 rather than 8+8 = 0, i don't know whether its just displaying the results as 0, or not displaying it at all, the code will follow below:
Code:
#include<iostream>
using namespace std;
double num3;
double num2;
double result;
char operation;
[Code] ....
creating a program using while that terminates the loop when two intergers any two between 1 to 100 are equal with each other
View 2 Replies View RelatedI calculate two numbers "R1",R2"
when i make
cout<<R1;
cout<<R2
i get
R1=51,9151
R2=51,915
when i make
Code: if (R1>R2) cout<<"i am here" he print the message
but they are equal. how i made limit the number of flottant to get equal numbers?
int main()
{
int a=0, c, d, N, K;
bool stopBool = 0;
[Code]....
This is supposed to find take a number N and K and find all numbers between 0 and N that equal K and cout the number of pairs that fit it but it doesn't work.
how to make a programm in native c++ which print out all prime numbers less than or equal to given number????????
View 5 Replies View RelatedIn my program I am supposed to call isEqualTo with a user defined class type, and print out if my two numbers being compared are equal or not. I had to write two versions of this, one with just a template which works fine, but when I implemented the class, all the sudden my program just spews out true no matter if actually equal or not. Here is what I have so far:
#include "stdafx.h"
#include <iostream>
#include "UserClass.h"
using namespace std;
template<typename T>
bool isEqualTo(T value1, T value2){
if (value1 == value2)
[Code] ....
how to split a file in equal size and when clicking on split button it split the files as well as encrypt split parts and the size information are automatically stored in groupbox and save all splitted files in folder.
View 1 Replies View RelatedI am trying to set a variable of type char equal to an element in an array of characters. For example:
char data[4] = "x+1";
char element;
element = data[2];
This seems like a logical progression from number arrays, but when I print both element and data[2], I get data[2] as expected, but element gives a different character every time (I assume a garbage value).
create a program that asks the user to input 10 integers of an array the program will add the numbers greater or equal to 10.
View 6 Replies View RelatedI have an assigment to make program which deletes from sentence all words with character count which is equal to pair number , for example - [ I like C ] and the result of this program should be [I C] because the word like contains 4 characters which is pair and it should be removed.
So I started writing my program and I am stuck at this block of code -
#include <stdio.h>
#include <stdlib.h>
main () {
char text[100], blank[100];
int c=0,d=0,i,j;
gets(text);
[Code] ....
To explain what is happening - I go through all string and search for first ' ' space symbol and check its value. If it is pair then my program prints that it is not pair[because last character before space had not pair number of characters], but the hardest part comes in when i have two not pair words , because space takes one character and now when i check if i%2 == 1 the answer is false [0] for the second word .
I was wondering if this was even possible and if so, how do I do it.
else if (speech.ToLower().Contains("truck") && speech.EndsWith(number))
{
Here I would like to see if my speech had ended with any of the values i would have stored in the string "numbers". If it did, I would like to just take the value and add it to a new string called whatever
}
I have tried this a million different ways and I cant get it to work. I'm not even sure how I would go about storing tons of different numbers in one string, or if that's even possible.