C++ :: Logical Operations Not Working?

Oct 7, 2014

int main()
{
char rORc, choice;
int sizerc;

[Code]....

when I input the character which is the underscore, and the row # it should display the table and sort that specific row. Why is the if statement skipped? This is not the complete program but has everything needed.

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C :: Binary Game - Using Values With Some Basic Logical Operations

Apr 24, 2014

When things at work get overwhelming, it's not unusual for me to briefly "escape" by writing small programs simply for fun. A few days ago, I had an idea for a "binary game". I completed the first draft of it yesterday.

The idea is simple. The game uses 8-bit values. At the start of the game, a random "target" value is generated. The player is dealt a "hand" of seven values. The object is to use the values in your hand, along with some basic logical operations, to create the "target" value. While the idea is simple, the game itself can be quite difficult.

Here is an example of the output:

Code: --------------------
T: 1111 1100 (0xFC)
--------------------
0: 0000 0000 (0x00)
--------------------
1: 1100 1110 (0xCE)
2: 1010 0011 (0xA3)
3: 1100 0101 (0xC5)
4: 1011 1111 (0xBF)
5: 1010 1011 (0xAB)
6: 0001 1011 (0x1B)
7: 0001 1011 (0x1B)
--------------------

: Looking at the first column:
- 'T' is the "target" value
- '0' can be thought of as the "game board" - this is the value that needs to match the target value for a win
- '1' - '7' are the values in your "hand"

You can apply logic AND ('A'), OR ('O'), or XOR ('X') to a value in your hand with the value on the "game board". You are also allowed to apply logic to two values in your hand to create a new value for your hand. When a value from your hand is used, it is removed.

Some examples of the commands:

A30 --- apply logic AND to value #3 in your hand, and the "game board" value
O23 --- apply logic OR to value #2 in your hand and value #3 in your hand
X70 --- apply logic XOR to value #7 in your hand, and the "game board" value

You can also be dealt new values (as long as there's room in your hand) with the '+' command. 'H' or 'h' prints the help, and 'Q' or 'q' exits the game.

I haven't thoroughly tested it yet, since I just finished it a yesterday, but so far it looks good. The program itself uses only standard C.

I was dickering with the idea of supporting more logical operators (NOT, NAND, NOR, XNOR, shift), but I like the simplicity and resulting difficulty of the current implementation.

During initial testing, I realized it's possible to have doubles in your hand. Also, it's quite possible to be dealt the target value directly, which means that you could potentially win with one move, chance permitting. At first I thought about defending against these conditions, but came to the conclusion that it is fine as is - chances of an instant win are small, and if it does occur, would still be an enjoyable experience. Besides, if you're dealt the target value after the "game board" value has been modified.

Also, I did not allow a value of "zero" in the players hand. This was originally because I thought it would be of little use (though I've been reconsidering this). This also means that if two values in the hand are combined and result in zero, both values are removed and no new value is added. This was originally a bug, but I think I'll just reclassify it as a feature

So far, I found that the best strategy is to avoid modifying the "game board" value, and just play with the values in your hand. If you can get the target value in your hand, you just OR it with the "game board" and you're done.

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C++ :: Using Logical Operators Like And Or

Dec 20, 2013

I wrote this program using an online compiler i am getting a lot of errors.

#include <iostream>
#include <string>
#include <sstream>
using namespace std;
int main() {
string birthmonth;
string birthday;

[Code] ....

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C :: Seg Fault Using Logical OR On For Loop

Mar 9, 2013

I've received a segmentation fault in this part of code:

Code:
for (; str[i] != '' || str[i] != ' '; i++) {
result[result_pos] = str[i];
result_pos++;
}

which, should mean:

Code: If str[i] is not equal to NULL character nor ' '; then, keep printing the chars within the word to variable result.

To understand what the function does, here's the whole code:

static char result[999];
/* char *split_word(const char *str, long n);
* Splits a string word-by-word. Where N is the word number. */
char *split_word(const char *str, long n) {

[Code]....

I'm trying to accomplish an easier way round to split string by word than using "strtok_r()". It might sound like "re-inventing the wheel", but... i will try to make it neat later.

The code looks okay, why would it segfault?

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C++ :: Casting A Logical Boolean As Int?

Jun 8, 2013

Let's say I have a product that needs service after 500 hours at 100 RPM. I can dsiplay the remaining hours only as an integer and we only have integer math. Management wants it to display 500 for the first hour, not 499 after the first minute is ticked off. But after a few minutes fullHours will be 499 and partialHours will have some value. I have 3 ways to determine displayHours to suit management and I want to know if the first is ligit.

short fullHours = 500;
short partialHours = 0;
short displayedHours = 0;

// Method 1 - Is is Kosher to cast a boolean as an int? Is TRUE always a 1 or is that a bad assumption?

displayedHours = fullHours + (short) (partialHours != 0);

//Method 2 - Works but some have disdain for the ternary conditional

displayHours = fullHours + (partialHours ? 1 : 0);

//Method 3 - seems a bit pedantic

displayHours = fullHours;
if (partialHours != 0) {
displayHours++;
}

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C++ :: Next Permutation Logical Error

May 11, 2013

I wrote this code to solve a problem in which the user inputs a permutation of size 'N' and the next permutation of the same elements has to be generated.

I went about this in this way: given 3 2 5 4 1, starting from the right, the first no. has to be searched which has a no. greater to it on its right. Here it is 2. Now an array is generated containing all no.s on its right and greater than it. For 2, it is: 5,4. Out of these the smallest member is searched for and switched with 2. So, 4 is switched with 2 to get the Next Permutation: 3 4 5 2 1.

The code I wrote does not show any error but does not return the correct value when run and gives the same value instead. If I enter '3 2 5 4 1' it returns the same value as the answer.

#include<iostream.h>
#include<conio.h>
void main() {
clrscr();
int N,M,i,n,c,swap,flag,count,small,m;
int Array[100],Key[100];

[Code] .....

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C++ :: Online Shop - Serious Logical Error

Nov 15, 2013

My project is on an online shop in which you can manage a shop(adding ,deleting ,clearing and modifying items) also you can switch to different shops(all shops are same)

Code:
#include<iostream>
#include<fstream>
#include<conio.h>
#include<stdlib.h>
#include<string.h>

[Code] ....

The logical problem is serious because i am not able to find the error!!! There is some problem with display lines in void shop()-->if(mode=='s') and if(mode=='d'). I add only one item but in output screen i see two items(sometimes >2)
*note* to run the above display lines in the output screen....first register--->add atleast one item--->see your shop

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C/C++ :: Multiply 2 Variables That Go From 0 To 7 - Logical Operators?

Apr 9, 2015

#include <iostream>
using namespace std;
int main(){
int polje[8][8];{
for(int i=0;i<8;i++)
for(int j=0;j<8;j++) {

[Code] .....

I don't get any errors,the program works. The problem is that it doesnt work how it should. This is a simple program that multiplies 2 variables(i and j)that go from 0 to 7. The problem I have is with the logical operators,i want the program to skip multiplication with 0 and when the 2 variables are the same value. When i try using only 1 logical operator it work.

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C++ :: Evaluating Logical Boolean Expressions

Jan 10, 2013

I am looking for a library to aid me in evaluating Boolean expressions. For example, i have an expression like this:

(1*(5+3)+9*65/5-(354*4565*5643+98) >= 12345) && ( 654*987+123 || (2345 > 23423 && 1 != 2)))

(It can also be much longer!) and would like to evaluate them to a true/false boolean.

There are tons of libraries to calculate the (numerical) result of a mathematical expression, but this is not what i want to do.

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C++ :: Logical Error In Output Of DAYNAME

Oct 31, 2014

I have to write a program that does the following: Monkey Business A local zoo wants to keep track of how many pounds of food each of its three monkeys eats each day during a typical week. Write a program that stores this information in a two-dimensional 3 - 7 array , where each row represents a different monkey and each column represents a different day of the week. The monkeys are represented by integers 1, 2, and 3; the weekdays are "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday". The program should first prompt the user to input the data for each monkey, starting with "Sunday" for monkey #1, then monkeys #2 and #3, followed by "Monday" for monkey #1, then monkeys #2 and #3 and so on, through "Saturday". The program then creates a report that includes the following information, each properly labeled (see below):

-Average amount of food eaten per day by the whole family of monkeys.
-The least amount of food eaten during the week by any one monkey.
-The greatest amount of food eaten during the week by any one monkey.

Input Validation: Do not accept negative numbers for pounds of food eaten. When a negative value is entered, the program outputs "invalid (negative) food quantity -- re-enter" and attempts to reread the value . Prompts And Output Labels: Decimal values should be displayed using default precision, i.e. do not specify precision. Each item read should be prompted for by a string of the form "Enter the food eaten by monkey #N on DAY:" when N is 1 or 2 or 3 and DAY is "Sunday" or "Monday" or ... or "Saturday".

The output should be of the form:

Average food consumed daily: 6.23
The least daily food consumed was by Monkey #0 on Friday
The most daily food consumed was by Monkey #2 on Sunday where the specific amount of food or specific monkeys or specific days identified depend on the actual input.

However after the process of resolving the errors unable to convert to standard string and unresolved externals I now have a logical error that causes the output of the DAYNAME variable to output as what appears to be hex in the following picture:

How I can fix this and why it's casting them as this in the output.

My full code is as follows because I don't know exactly, which line of code is causing this to happen:

Code:
//
#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
// constants
const int MONKEYS = 3;
const int DAYS = 7;

[Code] .....

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C :: How To Determine Whether A Logical Or Arithmetic Shift Is Performed

May 26, 2013

If input value was shifted to the right on bit level. How can I determine whether a logical or arithmetic shift is performed.

Code:
#include <stdio.h>
#include <stdlib.h>
void main ()

[Code]......

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C++ :: How Sub String And Math Can Be Used To Make Logical Decisions

Dec 1, 2014

This is an example of how sub string and math can be used to make logical decisions without using if/elses or switches. It works because of this equation

(x + |x|)/x = 2 if x > 0 and = 2 if x < 0.

#include <iostream>
#include <string>
#include <cmath>
using namespace std;
int main() {
//declaration of variables

[Code] ....

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C++ :: Logical Error - Change Value Inside Void Statement

Jul 16, 2013

I've encountered a slight logical error in my code

/*
Lab06_pensionplans.cpp
Purpose :
- Create a simple financial application to calculate retirement plans
*/
#include <iostream>
#include <cstdlib>
using namespace std;
void displayMenu() {
system("cls");

[Code] ....

Look at case 2, which the user supposed to key in a new input, the problem is the value will never got into main function, I don't know what should I modify with the function.

Figured out I need to change the

void changeData(int startingAge, int numOfYears,
double lumpSumAmount, double yearlyAmount, double interestRate )

into

void changeData(int &startingAge, int &numOfYears,
double &lumpSumAmount, double &yearlyAmount, double &interestRate )

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C++ :: Operations On Enumerations

Mar 12, 2014

I'm used to writing enums for enumerated types. However I have this:

enum Colour
{
BLUE = 0x01,
BLACK = 0x02,
WHITE = 0x04,
GREEN = 0x08,
RED = 0x10
};

Now each of the enumerated types are not exclusive, so I'd like to do this:

Colour c = BLUE | BLACK;

Of course that doesn't work. gcc gives "invalid conversion from 'int' to 'Colour' [-fpermissive]".

typedef int Colour;
static const Colour BLUE = 0x01;
static const Colour BLACK = 0x02;
static const Colour WHITE = 0x04;
static const Colour GREEN = 0x08;
static const Colour RED = 0x10;

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C++ :: Nested Conditional Operations

Feb 4, 2014

So I think I am having syntactical problem with my code.

Code:
int main() {
vector<int> ivec;
int score;
[Code] ....

I get an error from my compiler on the ?10th? line (Nested condition line) that says |19|error: invalid operands of types 'int' and '<unresolved overloaded function type>' to binary 'operator<<'|

The purpose of the program is to take input and store it in a vector and then change the value to be between 1-6. I made this for the purpose of learning about nested conditional operations.

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C :: Floating Point Operations

Mar 16, 2014

Code:
#include<stdio.h>
#include<conio.h>
void main()
{
float i;
i=0.7;

[Code] ....

If i do run the above program in turbo C/C++ complier, it outputs "h". But,if i change the code as i=0.6 and if (i<0.6), it outputs "w". Even if i change it to i=0.8 and if(i<0.8), then also it outputs "w".

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C++ ::  bitwise Operations On Numbers

Dec 8, 2014

Trying to write 4 bytes ints in a binary file and extract them after... I'm using the exclusive or (^) to isolate single bytes to write to and extract from the file since the write() function accepts only chars, only the beginning and end results are not the same...

#include <iostream>
#include <ctime>
#include <fstream>
#include <cstdlib>
using namespace std;

[Code] .....

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C++ ::  how To Handle Async Operations

May 29, 2013

I've been thinking over this for long time... For example, when a button is clicked, print a string "clicked" after 5 seconds. (the button won't be blocked)

Thread should be the only way to do this:

btn.on_click = []() {
thread thrd([]() { sleep_5_seconds(); cout << "clicked" << endl; });
thrd.start();
};

the local variable thrd is destructed right after it starts, which may cause a crash, so use new operator:

btn.on_click = []() {
thread* thrd = new thread([]() { sleep_5_seconds << "clicked" << endl; });
thrd->start();
};

The thrd never get deleted

How would you solve problem like this?

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C++ :: Validate Unsigned Operations?

Oct 12, 2012

I've sometimes encountered unexpected runtime issues caused by unsigned values being decremented below zero.

Example 1: "unsigned_value += negative_integer_value;"
Example 2: "for( size_t i = size - 1; i >= 0; --i )"

My compiler doesn't provide any compile-time or run-time warnings.

As far as I know, it's not possible to overload operators of primitive data types to check if the unsigned value is decremented below zero.

Any clever strategy to trace such cases at debug runtime, without having to add asserts all over the code? It's important that it does not affect performance in release mode.

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C++ :: Variable Length Integer Operations?

Aug 25, 2013

I intend to reference this thread from another thread so I do not clutter that thread with code

/* This code is relied on by some of the functions I will post */
typedef unsigned long long zxumax;
typedef signed long long zxsmax;

[Code]....

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C++ :: Mathematical Operations With Digits In Strings?

Feb 11, 2015

I'm working on a class project, and I'm having a difficulty. Suppose I have: string a = "21" and string b = "30"; normally, a+b=2130 (i.e concatenation of the characters in the string) but suppose I want a+b=51 (i.e. numerical addition) how do I go about this?

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C/C++ :: Console Input / Output Operations

Oct 27, 2012

How we can write coloured text to a text file in c? Can I use cprintf funtion with any kind editing

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C++ :: Incorrect Result In Bitwise Operations?

Oct 30, 2014

I'm doing a bitwise operations on 2 bytes in a buffer, then storing the result in a variable. However, I sometimes get a non-zero value for the variable even though I'm expecting a zero value.

The relevant portion of the code is as follows.

unsigned int result = 0;
long j = 0, length;
unsigned char *data;
data = (unsigned char *)malloc(sizeof(unsigned char)*800000);

[Code] ......

I'm expecting result to be zero when my data[j] and data[j+1] are 0xb6 and 0xab respectively, which is the case for most of the time. However, for certain values of j, my result is strangely not zero.

j = 62910, result = 64
j = 78670, result = 64
j = 100594, result = 64
j = 165658, result = 512
j = 247990, result = 128
j = 268330, result = 512
j = 326754, result = 1
j = 415874, result = 256
j = 456654, result = 1024
j = 477366, result = 512

It appears that these strange result values are all powers of 2, with a 1 bit appearing somewhere in the unsigned int.

I'm not changing the value of result anywhere else in the code, and when I print out (unsigned int)(((data[j]^0xb6)<<8)|(data[j+1]^0xab)), I get 0, but somehow when it gets stored in result, it's no longer zero.

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C :: Losing Contents Of A String Between File I/O Operations

Oct 24, 2013

Here's the code I'm writing:

Code:
#include <stdio.h>
#include <stdlib.h>
char* getTeamCode(char* team);

[Code]....

Why the placement of the code on line 21 above matters.

It grabs the correct string just fine. If I write a printf just below it, it prints the string it should correctly. However, if I do a printf of the string OSUteamCode below the fopen call on line 23, it prints blank.

So the first thing I did was move it below the fopen line. It worked, finding and outputting the first game in "game.csv" just fine, but not the other 11. Debugging with printf shows that the contents of OSUteamCode again disappear after the fopen call in the addLineCSV function.

I'm not understanding why that happens. The only thing I can figure is there's something going on with the file I/O commands that I just don't understand, but I can't find anything online that explains what that might be.

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C++ :: Limited Purpose Calculator Which Finds Value Of One Of Five Operations

Jan 9, 2015

I just started learning C++ a week ago and have been stuck on a project for the past 2 days now. I am building a limited purpose calculator which finds the value of one of five operations. Visual studio doesn't underline any errors in my program but every time I try to run it I get an error message. I believe it has something to do with the if/else but Im not sure.

#include <iostream>
using namespace std;
int main(){
int a;
int b;
int sum = a + b;

[Code] ....

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C++ :: Program To Complete Mathematical Operations Using Matrices

Jul 10, 2014

I've been assigned to build a program which completes mathematical operations using matrices. I have to use dynamically allocated 2d arrays, and can only use * to dereference and not []. I have this code so far, but the multiply_matrix function does not work with most values. I've looked at other similar posts, which have a similar algorithm to mine, but mine does not work for some reason.

/*
*(*matrix(matrix+i)+j)
*/

#include <iostream>
//for sleep() which allows user to see messages before screen is cleared
#include <unistd.h>
using namespace std;

[Code] .....

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