This code i made, utilizing the type casting construct, isn't outputting what i wanted. The output for 'Dollars' and 'Cents' are returning '0' for both. instead all i want it to do is seperate the two. for example changing the float value of amount to an integer, giving a dollar value.
Code:
#include <stdio.h>
int main()
{
}
[code]....
I find type casting to be very hard to grasp, I am not sure why. I understand how it works I suppose, but I find it hard to grasp why it would be needed in programming. So my question is, how often is type casting used in general programs? Is there an easier way I could be trying to teach myself about it? I am just using the tutorials provided by this site.
View 2 Replies View RelatedI came across some code and it's not clear why it is casting an unsigned char * to another pointer type only to free it right after. Here are the relevant structures:
Code:
struct _Edje_Message {
Edje *edje;
Edje_Queue queue;
Edje_Message_Type type;
int id;
unsigned char *msg;
[Code] .....
As you can see, _Edge_Message has a *msg field, but in the function below, they cast it to the other two structure types inside the case blocks of the switch statement only to free it. What is the point or advantage of doing this?
Code:
void
_edje_message_free(Edje_Message *em) {
if (em->msg) {
int i;
switch (em->type) {
[Code] ......
This program needs to display a vertical graph of asterisks showing production for each plant in the company ...
Here is what I have so far:
***********************************
This program will read data and
display a vertical graph showing
productivity for each plant.
Reference Display 7.8 pg. 401-3
***********************************
*/
#include <iostream>
[Code].....
I was interested in making a food ordering program utilizing voice commands. I hope to build a GUI with items listed on one side, and with voice commands picking up on key words that will add the food to the right of what you chose.
View 4 Replies View RelatedCode:
if (IS_LEAP_YEAR(year))
const int days_per_month[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
else
const int days_per_month[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; Is it ok to declare the array in this manner or is it bad?
And i have to ask the user for a date to enter in my program. So should I use scanf or should I store the date in a string and then use sscanf. I have to check for valid input for everything like day, month, year etc. I did it as below..
Code:
int assignments;
assignments = scanf("%d / %d / %d", &month, &day, &year);
fflush(stdin);
if (assignments != 3)
{
printf("Retry: ");
}
else
error checking.
This code i made divided a user input into characters and non character. The problem im having is that if a mixed sentence is created, such as 32B, it will only print the 'char string' and not the 'non char string'. But when the sentence is just non characters like 32 it will print the 'non-char string'. So essentially if a mixed sentences is created both of the strings won't be created or printed.(This is only a function by the way).
Code:
Count_chars( char Input[]) {
int i;
for(i = 0; Input[i]; i++) {
if((Input[i] <= 122) &&(Input[i] >= 97)){
printf("Char %c ",Input[i]);
Char[i] = Input[i];
[Code]...
I've a problem with the map construct. I wrote this class in which there are maps:
class Features {
private:
map<const string,GenericFeatureContainer*> featuremap;
map<const string,GenericFeatureContainer*>::iterator it;
int size;
public:
}
And I have the following constructor:
Features::Features() {
map<NULL,NULL> featuremap;
it=NULL;
size=0;
}
Is that correct? otherwise what is the correct syntax?
I'm trying to cast a float to an unsigned int and getting some surprising behavior.
Code:
float x = -1.0;
unsigned int y = (unsigned int)x;
printf("y = %d
", y);
The output of this code changes depending on which compiler I use. Sometimes I get -1 and sometimes I get 0. Not really sure why though.
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++;
}
I'm writing a small piece of code that increments through a string of numbers. For every 5 numbers a product is produced. However i'm having an issue understanding an error that keeps occurring.
#include <iostream>
#include <string>
#include <cstdlib>
[Code].....
if you look at the code i've got a string with 5 numbers 1-5 for testing. As the loop increments through the string it takes the first 5 characters and converts them to integers and then a product is returned. The issue is that instead of storing the single letter at position J its storing some combination from the string and as a result gives me a huge product. I tried debugging. I checked what the string[j] value was with a simple cout << and it returned the right number. I even returned the char value before it was converted into an integer and it was the right number.
double a = 1.0 + 1 + 1.0f; //everynumber will be added up as a double even the last one which is a float. All 3 numbers will turn into 3.0 as a double.
int x = (int)(7 + 3.0 / 4.0 * 2); //the variable will do the math bracket first. then the va type will still be an int because int was never changed.
Console.WriteLine((1 + 1) / 2 * 3); // 1 + 1 will be done first then 1 / 2 then * by 3
Console.WriteLine(x);
Console.ReadKey();
I THINK THATS ALL WRONG ^ =/ like the comments
double a = 1.0 + 1 + 1.0f;
In this equation, everything is using addition, so we start working left to right. 1.0 + 1 is the first step. These two representations of 1 aren't the same type though. In fact, none of the three are.
The first is a double, the second is an int, and the last is a float.
So in order to do 1.0 + 1, we need to convert one type to another. Since the double type is "wider" than the int type, we'll move things up to the double type. We'll convert the int version to a double, and to 1 + 1 using double types, resulting in 2.0 as a double.
Next we do the other addition. This has the same problem, though, because we'll be adding our result from the first step (a 2 as a double) to a float. So again, the float gets converted up to a double and we do the addition using doubles.
We now have a value of 3 that is the double type, which we can simply store in our a variable without any conversions at all, since our value is already a double type.
So, I've used int to float cast before. And it makes sense that it preserves the int value just converts it. I don't really need the answer, I'm just interested, and a resources could suffice.
1. Why in my test program it seems to preserve the int value, I expect that, but why for 0x8000 is it registering bit negation also. I know that is the negative bit for float, but it seems wrong. Is this an error in the gcc compiler conversion code?
2. What is the documentation on these type cast on how they actual work.
3. I know like no assembly, I'm wondering if some of the built in routines to handle or is it all c side code.
4. Can I convert type and preserve the bits. Maybe use void* casting ? I've never really bothered with void* so I don't all that I can do. Except be a pointer that doesn't know the type, obviously. I tested that out in the second code, the output doesn't seem correct, except -0.000. Is it working and my test numbers just are improper float format? It can't be that I test 0x3E20000 = 0.15625 from SingleWiki , but I got 1.328e-36 so the int to void* to float doesn't seem to work in the code below:
#include <cstdio>
int main(){
float flout;
unsigned int num = 1;
int ant;
printf("Int Shift float");
for(unsigned int shift=0;shift<32;shift++){
[Code] ....
Casting Pointers in C Programming. I don't want to move onto implicit casts until I have this down pat. I'm failing to understand how casting pointers works.
The line
int *mnt = (int*)&flt;
if I read this correctly passes the address of flt which has been converted to an int to the pointer mnt.
1 - When I output mnt I get a garbage value, probably because the address of flt is then converted to a pointer and passed onto mnt as a value and then reinterpreted as a memory address. (that is the first part I don't understand)
2 - - What exactly does the (int*) cast say? Does this mean that a pointer will be returned or an address will be returned. What does the fact that the * is inside the parenthesis mean?
Code:
#include <iostream>
using namespace std;
int main() {
float flt= 6.5;
int *mnt = (int*)&flt;
cout << mnt << endl; // outputs hex memory address
cout << *mnt << endl; // outputs garbage value
}
I am writing code, which reads an input file (280 MB) containing a list of words. I would like to compute
1) total # of words
2) total # of unique/distinct words
3) mean/median/mode of word count (Link)
I managed to get done with 1) and 2), but my program crashes for 3). I am not quite sure whether there are memory issues or some bug in the code.
Code:
#include <iostream>
#include <fstream>
#include <string>
#include <map>
using namespace std;
[Code] .....
How to construct a simple hash function ? When the program executes, it will ask for your name. Type your name and it will print out a "hash code" (a number) from that name.
View 2 Replies View Relatedhave a problem with my code (I wish for answer with code). The conditions I have to grant:
- **Only** a pointer to an object must be saved in a **standard** class vector (e.g vector<ShapePtr>)
- Base class must be a polymorphic class (I call this class ShapePtr)
- I **must** have a deep copy process
- Constructor is **not** suppose to do a deep copy
- **clone()** is suppose to do the deep copy
Here is the code **provided** to me:
main.cpp
int main() {
typedef shared_ptr<Shape> ShapePtr;
vector<ShapePtr> shapevec;
[Code].....
If I have an integer variable like int a=9 then in the switch case If i write :
switch(a) {
case 4+a: printf("hii");
}
Then why is this statement a compile-time error that variables cannot be used inside a case statement why does the compiler not subtitutes the values in place of the variables.
I am doing an exercise which has to do with International country codes.The user must give a code and the programm will display the corresponding country.
Code:
#include <stdio.h>
#define COUNTRY_COUNT
((int) (sizeof(country_codes) / sizeof(country_codes[0])))
[code]....
I am just getting back in to C++ after 10 years not doing any, contributing to an open source project. I'm adding in some functionality and am hitting a road block.
I need to send a multicast packet out on the network that is structured in a certain way. I have the definition, and know what data is going in each byte. I can successfully send a message using multicast, I now just need to send the right message.
I have used a char array to hold the message, as each char represents 1 byte, and I can transmit the array.
I am having trouble putting all of the data in the right place though. If my source data is a string, then I seem to be able to convert it, but if it is a short or int, then I keep getting errors when compiling. Similarly, two of the lines, (version and type) i initially tried using char arrays with a length of one.
Should I be using memcpy or a different function, or even be doing this in a totally different way altogether? This is the code that I am using, along with the packet structure:
//Construct a Zone Query packet
// 4 bytes - Signature "Ohz " = 0x6f, 0x68, 0x7a, 0x20
// 1 bytes - Version = 1
// 1 bytes - Type (0 = Zone Query, 1 = Zone Uri)
// 2 bytes - Entire message length = 12 + zone length
// 4 bytes - Length in bytes of the zone ID
// n bytes - Zone ID to query
[Code] ....
The errors that I get are:
error: invalid conversion from ‘short int’ to ‘const void*’ [-fpermissive]
memcpy(buffer + 6, packetLength, sizeof(packetLength));
^
[Code] ....
So I have a vector of 8bit variables. Is it possible to cast that to a vector of 6bit variables like...
8bit: 10011011 01100011 ===>
6bit: 100110 110110 0011XX
This code i made is a cent converter from 5 to 95 cents. The problem i'm receiving is when the 'cents' function is sent back to the 'main' function it only prints one line. It seems to just print the first if construct that complies with the statement. Is there anyway i can have this function print multiple cent values? For example if 60 cents was entered it would only print '50c', and i want it to print '50c' and '10c' instead.
Code:
#include <stdio.h>
int x;
void check(int x)
{
if( x < 5)
printf("Less then 5 cannot be calculated
");
else if(x > 95)
[code]....
how to read characters from user and construct a sting and then extract part of it using substring?
View 2 Replies View RelatedI am trying to construct a program without a main function that outputs stars but at the same time outputs the number and a colon after the number but before the number of star. This is the coding i have so far.
void output_stars(int num){
if (num > 0){
cout << "*";
output_stars(num-1)
[Code] ....
The program is working the way it should i just can't figure out how to output the number and a colon. The main function is written as such:
output_stars(1);
output_stars(2);
output_stars(5);
output_stars(3);
output_stars(4);
output_stars(7);
How to get the numbers of the main function to show up with the stars of the previous function.
I'm trying to read a "pointer-based" maze .txt. The first letter in each row corresponds to the room letter...then the letters that follow are North node, East node, South node, and West node respectively. The asterisk indicates an empty room or not a valid option.
Here is what I have come up with, what is happening is after the file is parsed by read_maze it is calling my is_empty function indicating that there is no maze because it doesn't go into the else statement here.
I've attached a sample input file:
maze.txt (130bytes)
Number of downloads: 19
We can't assume the rooms will be in order alphabetically A - Z, We are expecting a maximum of 12 rooms and there is a space between each letter or asterisk.
void Maze::read_maze(string FileName){
string line;
ifstream inStream;
inStream.open(FileName.c_str());
int test = inStream.peek();
int i = 0;
if (!(inStream.fail())){
while (!inStream.eof() && test != EOF){
[code]....
I just wanted to ask the reason that why is the below code not checking the case -1 while working for the other case values.
#include<stdio.h>
#include<conio.h>
int main() {
int i=-1;
switch(i-2) {
[Code] ....
So why in the below code the case -1 doesnt run,when the value evaluated by the switch construct is actually a negative integer constant.