C++ :: Determines Whether A Number Which User Inputs Is Prime Or Not

Jan 11, 2015

I am fairly new to C++ and I am trying to write a code that determines whether a number which the user inputs is prime or not. I have the code, but when I run it all it actually does is report odd numbers as prime and even numbers as not prime.

#include <iostream>
using namespace std;
//declaring variables//
int i;
int num;

[Code] ....

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C :: Program That Allow User To Enter A Number N And Print Nth Prime Number

Nov 3, 2013

I need to write a program that will allow the user to enter a number "n" and the program tell you that the nth prime number is .....

EXAMPLE

user enters 55

printf("The 55th prime number is %i", variable");

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C++ :: Receive Number From User And Output Largest Prime Number

Nov 20, 2014

I am attempting to write code that receives a number from the user and outputs the largest prime number underneath the user's number. There are no errors in my code, but no matter what number is imputed, the program says the largest prime number is 1. I cannot find where the issue is in the code. Here is the code I wrote:

#include <cstdlib>
#include <iostream>
#include <cmath>
using namespace std;
bool isPrime(int num);//function prototype

[Code] ....

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C++ :: Random Number Generator - How To Get User Inputs

Sep 10, 2013

I want to program a program that produces a random number between 1-10, then if the number is correct, says like HEY GOOD JOB and if its not says try AGAIN! also, at any point the user can quit by typing in X.

I know that I can use stuff like cout << "Hey put in a guess now" to prompt the user but I dont know how to accept inputs.

For example, how do I use scanf to do this?

I know that if I use scanf, it takes in a value, but where the heck does it store it?

eg. scanf(%s,guess);

Is that valid? I get an invalid expression error when trying to use that in C++.

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C/C++ :: User Input - Number Prime Or Composite?

Mar 8, 2014

User will input a number in the range of 2 and 2^63-1 and the program will decide whether it's prime or not by a simple 'YES' or 'NO'.

I figured out a code:

#include <stdio.h>
#include <string.h>
main() {
unsigned long long n,i=3; int temp=0;
int t;
scanf("%d",&t); //Number of test cases

[Code] ....

Now this code works for normal inputs but whenever I try it with large primes in tat range, like 987654321987654329 or 9223372036854775783 it does not work />.

I tried to print the values of i to check the limit to which it runs.. and I found it 23697, whose square is 561547809 - nowhere near about the input primes.

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C++ :: If User Inputs Letters / Words Instead Of A Number Give Error Message

Jan 11, 2014

I have created an error message if the user inputs the wrong selection number

if (choices < 1 || choices > 5)
{
cout << "
Please Enter a number between 1-5
";
}

How would i create a error message if the user inputs letters/words instead of a number.

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C/C++ :: Find Prime Factors Of Number Input By User?

Apr 21, 2014

find the prime factors of the number input by the user. This time, we are going to have the user input a number, and the program will find all prime numbers from 2 to that number and prime factors of the number input by the user

#include <iostream>
#include <cmath>
using namespace std;

[Code]......

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C++ :: Write Program Which Tells User If Number They Input Is Prime Or Not?

May 2, 2014

So I need to write a program which tells the user if the number they input is prime or not. I have done so and included the code below. My problem is that I need to allow the user to input if they want to enter another number after the first one using y or n and I am having trouble figure it out.

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

[Code].....

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C :: Write A Code To Find All The Prime Numbers Before A User Entered Number

Apr 9, 2014

I am trying to write code to find all the prime numbers before a user entered number. I started with a working program and when I tried to create a function, it got all messed up.

Code:

#include <stdio.h>
int is_prime( int num );
int get_positive_integer(void);
int main( ) {
int upper; /* upper limit to check */
int num; /* current number to check */
int isprime;
/* used to flag if number is prime or not */

[Code]...

It says the error is on line 23

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C++ :: Prime Number Program Not Working With Odd Non-prime Numbers

Dec 2, 2014

I have a program that gets prime numbers that doesn't work. It looks like it works for all prime numbers except odd non-prime ones. Here is the code:

Code:
#include <iostream>
using namespace std;
bool isPrime(int prime) {
while(true) {
int track = 0;

[Code] ...

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C/C++ :: Finding All Prime Numbers To Nth Prime Number

Aug 24, 2014

I'm a new coder for C++, and I've recently learned java before starting this programming language. I'm attempting to find all prime numbers up to the number a user enters (i.e. User enters 10, System shows "1,2,3,5,7"),

#include <iostream>
#include <cstdlib>
using namespace std;
int main(int argc, char** argv) {
int num;
cout << "Enter a positive number." << endl;

[Code] ....

I've been looking at my forloop, and I can't seem to pinpoint the problem with it.

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C :: 2 User Inputs For Calculation

Apr 9, 2014

I want to have calculations take place inside a switch statement that calls the appropriate function. The menu portion of the program works well, but I can't figure out how to let the user actually input 2 different numbers to the functions. My questions are:

1. If I use scanf to assign values to the variables, what determines end of input to each variable? (ie.. scanf("%d%d", &a, &b) what is the end of a, what is the end of b?)

2. Should I assign the variables to user input inside the switch, or try to do it in the functions below?

3. Is there something I haven't thought to ask that will screw me over? I'm really new to this.

Code:
#include<stdio.h>
int add(int b, int a);
int mult(int b, int a);
main() {

[Code] ....

This really was a test of multilayer menu, but I want to add functionality if I can.

Changed a variable before posting and didn't change all the conditions testing it.

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C :: Keep User From Putting Inputs

Sep 27, 2013

On my program I use a counter to count to 10, then i ask for a string, in this case "yes" or "no", during the count, i want to keep the user from putting inputs in, due to the fact that if they put both "yes" and "no" before the program reads the string.

Code:

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <stdbool.h>
#include <time.h>
#include <string.h>
}

[code]....

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C :: How To Put What The User Inputs Into Array

Jul 23, 2014

I have a project that requires I take user input from menu options and put it into an array which I will average out. I can set the menu up I think, but I cannot understand how to put what the user inputs into an array. Granted I just took the lecture on arrays today. Also we can only use functions to do the work.

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C/C++ :: How To Get User Inputs Into Array

Mar 16, 2014

How to get user inputs into an array. I have to get 10 user inputs into the array and I'm trying to use a loop but once I run it it crashes whenever you input the first value. This is my absolute first time working with arrays and I've been trying to do research

#include <stdio.h>
#define SIZE 10
void Input(const int array1[]);
void Calculations(int array1[], int average);
void Output(int array1[], int average);

[Code]....

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C :: Picking And Choosing Between User Inputs

Jul 31, 2013

I have recently looked into a self created project where I wanted to compare user input against a list of strings in an external file. That has since been completed to my great satisfaction, however it did throw up some interesting issues in my knowledge and understanding of user input..What is the best way to pick up user input i.e scanf,stdin etc. and when should either be used and can a mixture of types be used, and if so, when and why.

A quick program to take different input methods and display differnt output method (obviously corresponding i.e scanf/printf - fgets/fputs)

My first pothole came when I have setup the method for scanf - fine. Then I setup the method for fgets(test,100,stdin) for example and the fgets method no longer picks up stdin from the user..

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C++ ::  calculating Sum Of Numbers Between Two User Inputs

Mar 17, 2014

How to calculate the values between numbers that a user types in.

Write a function which takes two parameter of integer type and both parameters are positive integer. These number should be provided by the user of your program. The first parameter is lower than the second parameter. You function should be able to calculate the sum of the square of each of the numbers between the two inputs and should display that. Please write a main function to display the working of your function. Call the function at least three times by using some loop in the main function.

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C/C++ :: Linked List Inputs From The User?

Sep 8, 2014

#include <iostream>
using namespace std;
void insert(int data, int positionOf_n);
void print();
struct node {
int data;
struct node *next;

[code]....

this is the original code which use the insert function call in the main as predefined that doesn't allow the user to input the value that they want

#include <iostream>
using namespace std;
void insert(int data, int positionOf_n);
void print();
struct node {
int data;

[code]....

and this the code which i tried to replace the limitation of the above code by using two for loops in the main function instead of the <insert(5,2)> from the above code which allow the user to insert it own values to the linked list, but it keeps crashing.

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C :: Stomp Size Of Array With What The User Inputs?

Apr 5, 2013

How can I stomp the arr size of 50 with the value the user inputs? The function doesn't sum up the even integers from 0 to the value the user inputs. Instead it sums up exactly that many even integers.

Is there a way I can stomp the size of the array with what the user inputs so that the sum calculation never goes past the value the user inputs?

Code:
void sumIntegers () {
int arr[50];
int i = 0;
int num = 0;
int sum = 0;
printf("

I want to sum up even integers <= 50.

[Code] .....

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C++ :: For Loop - Summing Numbers (Inputs From User)

Aug 2, 2013

Write a program that computes a running sum of inputs from the user, terminating when the user gives an input value of 0

Using a while loop - no problem. Its only when I try to code it with a for loop that the program doesn't terminate with a 0 input. It terminates with a -1 input!!

while loop

#include <iostream>
using namespace std;
int main() {
float input=1;
float sum = 0;

[Code] ....

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C++ :: Create Fibonacci Sequence With Some User Inputs

Aug 26, 2013

I'm trying to make a fibonacci sequence with some user inputs. I'm using arrays for this, the user inputs are for the Nth term and the starting number (as in the number in front of 0).

My problem is that when the program runs it's an infinite loop which constantly prints the starting number. Which, I think, means that my WHILE loop isn't coming to an end and my 'count' variable isn't increasing.

#include <iostream>
using namespace std;
int main() {
int start;
int term;
cout << "Input a starting number for the sequence: ";
cin >> start;
cout << "
Enter the Nth term for the sequence to reach: ";

[code].....

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C++ :: Templates User Inputs Dynamic Array?

Nov 12, 2013

This code is from my text book it shows how to implement code that is embedded I have modified it somewhat but I was wondering how I could get the user to implement the size of the array and enter the integers with the size of array that was implemented.

#include<iostream>
#include<cstdlib>
#include<iomanip>
using namespace std;

[Code].....

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C++ :: Create A Grading Program That The User Inputs A Name?

Feb 17, 2013

I want to create a grading program that the user inputs a name and then on that value (name) there is a vector of doubles to represent his/her mark and then calculates an average how would I go about doing this?

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C++ :: Using Char To Check Whether The User Inputs The Right Command?

Mar 20, 2014

I've been trying to finish this airplane seating program I've been working on for a month or two. The problem I have right now is that if the user inputs a number when prompted to enter the column letter he wants, the program goes on to the next step as if the prompt had been answered correctly.

So I originally used string but I heard from Daleth that Char was better, but I don't know how to apply it. I figured out cin.fail, but I've yet to finish this part.

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C++ :: When User Inputs It Doesn't Show The Function

Aug 2, 2014

#include <iostream>
#include <iomanip>
#include <fstream>

[Code]....

i have already tried putting system pause or cin.get after it, but no luck

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C :: Give Error Message If User Inputs Wrong

Nov 2, 2013

Code:

#include<stdio.h>
void main
{
int i;
int marks[10];
}

[code]....

how to give error and ask user to re enter if user enter other then a number?

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