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C++ Articles
Page 536 of 597
What are undefined reference/unresolved external symbol errors in C++?
As the name suggests, a symbol you declared was not defined by you. This may occur due to many cases. Let's have a look at three of them −You forgot to define the declared name. For example, you declared a function in a file and used it somewhere. But you did not provide its definition. Code −#include void foo(); int main() { foo(); // Declared but not defined }You defined it but did not use the qualified name. Say you created a class with a method and defined that method but forgot using scope resolution to link that function ...
Read MoreWhy we can't use arrow operator in gets and puts?
You can't read user input in an un-initialized pointer. Instead, have a variable of the struct data type and assign its address to pointer before accessing its inner elements by → operatorexample#include struct example{ char name[20]; }; main(){ struct example *ptr; struct example e; puts("enter name"); gets(e.name); ptr=&e; puts(ptr->name); }OutputTypical result of above codeenter name Disha You entered Disha
Read MoreWhat are the basic rules and idioms for operator overloading in C++?
When it comes to operator overloading in C++, there are 3 basic rules you should follow. like all such rules, there are so exceptions. These 3 rules are −1. Whenever the meaning of an operator is not obviously clear and undisputed, it should not be overloaded. Instead, provide a function with a well-chosen name. Basically, the first and foremost rule for overloading operators, at its very heart, says:Don’t do it.That might seem strange, but there are only a few cases where operator overloading is appropriate. The reason is, it is hard to understand the semantics behind the application of ...
Read MoreWhat is ternary operator (? X : Y) in C++?
The conditional operator (? :) is a ternary operator (it takes three operands). The conditional operator works as follows −The first operand is implicitly converted to bool. It is evaluated and all side effects are completed before continuing.If the first operand evaluates to true (1), the second operand is evaluated.If the first operand evaluates to false (0), the third operand is evaluated.The result of the conditional operator is the result of whichever operand is evaluated — the second or the third. Only one of the last two operands is evaluated in a conditional expression. The evaluation of the conditional operator ...
Read MoreDifference between Set and MultiSet in C++
In C++, both Set and MultiSet are the type of data structures which are used to store the data for easy accessing and insertion. On the basis of characteristics of both these data structures we can distinguish between Set and MultiSet.Following are the important differences between Set and MultiSet −Sr. No.KeySetMultiSet1DefinitionSet in C++ can be defined as a type of associative container which stores the data in key value pair and in which each value element has to be unique, because the value of the element identifies it.On other hand MultiSet are part of the C++ STL (Standard Template Library) ...
Read MoreNumber of Paths with Max Score in C++
Suppose we have a square board of characters. We can move on the board starting at the bottom right square marked with the character 'S'. Now we need to reach the top left square marked with the character 'E'. The other squares are labeled either with a numeric character from 1 to 9 or with an obstacle 'X'. In one move we can go up, left or up-left only when there is no obstacle there.We have to find the list of two numbers: the first number is the maximum sum of the numeric characters we can collect, and the second ...
Read MoreBinary Tree Cameras in C++
Suppose we have a binary tree; we place cameras on the nodes of the tree. Now each camera at a node can monitor its parent, itself, and its children. We have to find the minimum number of cameras needed to monitor all nodes of the tree.So, if the input is like −then the output will be 1, because only one camera is enough to track all.To solve this, we will follow these steps −Define one set called covered, of type TreeNode (Tree node has left, right and data field)Define a function solve(), this will take node, parent, if node is ...
Read MoreStream of Characters in C++
Suppose we want to implement the StreamChecker class as follows −StreamChecker(words) − This is the constructor, this initializes the data structure with the given words.query(letter) − This returns true when for some k >= 1, the last k characters queried (in order from oldest to newest, including this letter just queried) spell one of the words in the given list.So, if the input is like word list = ["ce", "g", "lm"], then call query many times for [a, b, c, e, f, g, h, i, j, k, l, m], then the output will be true for e, g, m, and ...
Read MoreBrace Expansion in C++
Suppose we have a string S that represents a list of words. Here each letter in the word has 1 or more options. If there is only one option, the letter is represented as is. If there is more than one option, then curly braces delimit the options. So for example, "{a, b, c}" will represent the options ["a", "b", "c"]. Now for example, if the input is like "{a, b, c}d{e, f}" this will represent the list ["ade", "adf", "bde", "bdf", "cde", "cdf"]. Return all words that can be formed in this manner, in lexicographical order. To ...
Read MoreReveal Cards In Increasing Order in C++
Suppose we have a deck of cards; every card has a one unique number. We can order the deck in any order that we want. So Initially, all the cards start face down (unrevealed) in one deck. Now, we do the following steps multiple times, until all cards are revealed − Take the top card off the deck, reveal it, and answer with it. If there are still cards in the deck, then put the next top card of the deck at the bottom of the deck. If there are still unseen cards, go back to step 1. Otherwise, ...
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