This is my code to find facotrial of a number and to find number of occurunces of all digits in the factorial.
#include <stdio.h>
#include <stdbool.h>
int iFactorial(int iCount)
{
int iProduct = 1;
int iNumber = 1;
while (iNumber <= iCount)
{
iProduct *= iNumber;
iNumber++;
}
return iProduct;
}
int main(void)
{
int iFac[10] = {0};
int iCount = 0;
printf("Please input a Integer: ");
scanf("%d",&iCount);
iFac[iCount] = iFactorial(iCount);
printf("\nThe value of the factorial of %d is %d\n",iCount, iFac[iCount]);
int i;
int dig[10] = {0};
while (iFac <=0)
{
int n;
n= ((iFac % 10) + 1);
dig[n] = dig[n] +1;
iFac = iFac / 10;
}
for (i = 0; i > 9; i++)
{
if (dig[i+1] >0)
{
printf ("%d %d\n", i, dig[i+1]);
}
}
}
I need to find the proper method for writing array[x] = array[x] + 1
I think following code will clear how you wanted to count the digits.
#include<stdio.h>
int factorial (int n)
{
if ( n == 1 ) return 1 ;
return n * factorial( n-1 ) ;
}
int main()
{
//Input number
int num ;
scanf( "%d", &num ) ;
//Calculate Factorial
int fact = factorial ( num ) ;
cout<< "\nFactorial of Number is " << fact ;
//Count the frequency of Digits
int dig[10] = {0} ;
while( fact )
{
int i = fact % 10 ;
dig[i]++ ;
fact /= 10 ;
}
for ( int i = 0 ; i < 10 ; i++ )
printf("\n The digit %d is present %d times " , i , dig[i] );
return 0 ;
}
Make sure you dont input large values for calculating the factorial for a number.
Related
So I started learning C language for Uni and got stuck with this exercise, I found a way to ge the prime numbers of a number but I don't know how to multiply the prime numbers and display them.
int main()
{
int number;
int prime;
int i,j;
printf("Insert number:");
scanf("%d", &number);
printf("Prime numbers of %d are: ",number);
for(i = 2; i <= number; i++)
{
prime = 1;
for(j = 2; j <= i/2; j++)
{
if(i % j == 0)
{
prime = 0;
}
}
if(prime == 1)
{
printf(" %d", i);
}
}
return 0;
}
You need to introduce one more variable that will store the nultiplication of prime numbers.
Here is a demonstration program.
#include <stdio.h>
int main( void )
{
unsigned int number;
printf( "Insert number (0 - exit ): " );
if ( scanf( "%u", &number ) == 1 && number != 0 )
{
if ( number < 2 )
{
printf( "There are no prime numbers in the range [0, %u].\n", number );
}
else
{
unsigned long long product = 2;
printf( "Prime numbers in the range [0, %u] are: ", number );
printf( "%u ", 2 );
for ( unsigned int i = 3; i <= number; i += 2 )
{
int prime = 1;
for( unsigned int j = 3; prime && j <= i / j; j += 2 )
{
if ( i % j == 0 )
{
prime = 0;
}
}
if ( prime )
{
printf( "%d ", i );
product *= i;
}
}
printf( "\nTheir multiplication is equal to %llu\n", product );
}
}
}
Its output might look like
Insert number (0 - exit ): 10
Prime numbers in the range [0, 10] are: 2 3 5 7
Their multiplication is equal to 210
I wrote this program to find prime numbers between 1 and 50000, and I still need to find how many prime numbers there is (I tried a lot of tricks but I did not succeed)
#include <stdio.h>
//int getValueFromUser();
void PrintListOfPrime(int value);
int main() {
int value = 23;
PrintListOfPrime(value);
return 0;
}
void PrintListOfPrime(int value) {
int ValueIsPrime; //ValueIsPrime is used as flag variable
printf("The list of primes: ");
for (int i = 2; i <= value; i++) {
ValueIsPrime = 1;
/* Check if the current number i is prime or not */
for (int j = 2; j <= i / 2; j++) {
/*
* If the number is divisible by any number
* other than 1 and self then it is not prime
*/
if (i % j == 0) {
ValueIsPrime = 0;
break;
}
}
/* If the number is prime then print */
if (ValueIsPrime == 1)
printf("%d, ", i);
}
printf("\n");
}
I tried a lot of tricks but I did not succeed
If OP's code takes too long to ran, iterate to the square root of i, not up to i/2.
j <= i / 2 is very slow. Use j <= i / j instead.
Form a count and increment with every prime. #gspr
if (ValueIsPrime == 1) {
printf("%d, ", i);
prime_count++;
}
Bigger change yet even faster to "find prime numbers between 1 and 50000", research Sieve of Eratosthenes
Hello fast answer is to create a variable in main, int totaleOfPrimes = 0; for example.
then send it by reference to the fucntion :
Function declaration : void PrintListOfPrime(int value,int* counter);
Function call : void PrintListOfPrime(value,&totaleOfPrimes);
then Increment counter befor printing :
if (ValueIsPrime == 1){
(*counter)++;
printf("%d, ", i);
}
There is no need to iterate the loops for all numbers between 2 and value. You should consider only 2 and odd numbers.
The function can look the following way as it is shown in the demonstrative program below.
#include <stdio.h>
static inline size_t PrintListOfPrime( unsigned int n )
{
size_t count = 0;
printf( "The list of primes:\n" );
for ( unsigned int i = 2; i <= n; i = i != 2 ? i + 2 : i + 1 )
{
int isPrime = 1;
/* Check if the current number i is prime or not */
for ( unsigned int j = 3; isPrime && j <= i / j; j += 2 )
{
/*
* If the number is divisible by any number
* other than 1 and self then it is not prime
*/
isPrime = i % j != 0;
}
/* If the number is prime then print */
if ( isPrime )
{
if ( ++count % 14 == 0 ) putchar( '\n' );
printf( "%u ", i );
}
}
return count;
}
int main(void)
{
unsigned int n = 50000;
size_t count = PrintListOfPrime( n );
printf( "\n\nThere are %zu prime numbers up to %u\n", count, n );
return 0;
}
Run this code in C. It will return the value of a pi(x) function. It is basically the Prime counting function:
#include <stdio.h>
#define LEAST_PRIME 2
#include <math.h>
int main() //works for first 10000 primes.
{
int lower_limit = 2, no_of_sets;
// printf("NUMBER OF SETS: ");
// scanf("%d", &no_of_sets);
int remainder, divisor = 2, remainder_dump, upper_limit; //upper limit to be specified
//by user.
int i = 1;
// printf("SPECIFY LOWER LIMIT: ");
// scanf("%d", &lower_limit);
int number_to_be_checked = lower_limit;
printf("SPECIFY UPPER LIMIT: ");
scanf("%d", &upper_limit);
printf("2\t\t\t\t", number_to_be_checked);
//PRINTS 2.*/
do
{
remainder_dump = 1;
divisor = 2;
do
{
remainder = number_to_be_checked % divisor;
if (remainder == 0)
{
remainder_dump = remainder_dump * remainder; // dumping 0 for rejection.
break;
}
++divisor;
} while (divisor <= number_to_be_checked / divisor); // upto here we know number
is prime or not.
if (remainder_dump != 0)
{
++i;
printf("%d.\t\t\t\t", number_to_be_checked); //print if prime.
};
number_to_be_checked = number_to_be_checked + 1;
} while (number_to_be_checked <= upper_limit);
printf("\n pi(x) = %d \n", i);
//printf("pi function value is %f.", (i - 1) / (log(i - 1)));
float app;
app = upper_limit / (log(upper_limit));
float plot_value;
plot_value = (i) / app;
printf(" BETA FUNCTION VALUE ~ %f", plot_value);
return 0;
}
I wrote a simple program in c that accepts two numbers and then splits the first number considering the digits of the second number like this:
Input:
362903157 2313
Output:
36
290
3
157
Everything works just fine, except when there are zeroes in the first number, my program skips them. For instance the upper example gives me this output:
36 293 1 570
And that is mycode:
#include <stdio.h>
int nDigits(unsigned i) {
int n = 1;
while (i > 9) {
n++;
i /= 10;
}
return n;
}
// find the highest multiple of 10
int multipleOfTen(int num){
int multiple = 1;
while(multiple <= num){
multiple *= 10;
if(multiple > num){
multiple /= 10;
break;
}
}
return multiple;
}
int main(){
int n, m, digit;
scanf("%d %d", &n, &m);
int lengthOfM = nDigits(m);
for (int i = 0; i < lengthOfM; i++){
digit = m / multipleOfTen(m); //2
for(int j = 1; j <= digit; j++){
printf("%d", n/multipleOfTen(n));
n = n% multipleOfTen(n);
}
printf("\n");
m = m % multipleOfTen(m);
}
return 0;
}
What should I change in my program so that the zeroes won't be ignored?
Instead of calling multipleOfTen() in each loop, call it once and save the result for both n and m. Then in each loop divide those results by 10
#include <stdio.h>
int nDigits(unsigned i) {
int n = 1;
while (i > 9) {
n++;
i /= 10;
}
return n;
}
// find the highest multiple of 10
int multipleOfTen(int num){
int multiple = 1;
while(multiple <= num){
multiple *= 10;
if(multiple > num){
multiple /= 10;
break;
}
}
return multiple;
}
int main(){
int n, m, digit;
int i, j;
int n10, m10;
scanf("%d %d", &n, &m);
int lengthOfM = nDigits(m);
n10 = multipleOfTen(n); //get the multiple of ten once
m10 = multipleOfTen(m);
for ( i = 0; i < lengthOfM; i++){
digit = m / m10;
m10 /= 10;
for( j = 0; j < digit; j++){
printf("%d", n/n10);
n = n% n10;
n10 /= 10;// divide by 10
}
printf("\n");
m = m % multipleOfTen(m);
}
return 0;
}
I suppose an approach like this is inadmissible?
#include <stdio.h>
#include <string.h>
int main ( void ) {
char n[64];
char m[64];
char * p = n;
int i = 0;
int c;
scanf("%63[0-9] %63[0-9]", n, m);
while ((c = m[i++]) != '\0') {
int j = c - '0';
while (j-- > 0) if (*p) putchar(*p++);
putchar(' ');
}
putchar('\n');
return 0;
}
when n=903157 and after n = n% multipleOfTen(n); n becomes 3157 not 03157 so when u dividing again in line printf("%d", n/multipleOfTen(n)); it prints 3 not 0 what you want!!
Fix your code to produce right output.
Well, I wrote the code and everything is fine except one thing.
When I enter that digit number, which has to be upto 10 digits, I recieve in arr[0] various values, for example, if I enter "12345" I get 20, 1 , 1 , 1 , 1 , 1 , 0 ,0 ,0 ,0.
Which is fine from arr[1] to arr[9], but pretty odd in arr[0].
Any ideas?
#include <stdio.h>
#include <conio.h>
#include <math.h>
void main()
{
int i,j,p=0, temp,indexNum, arr[10] = { 0 }, num, level = 10, level2 = 1,maxIndex;
printf("Please enter a digit number (upto 10 digits) \n");
scanf("%d", &num);
temp = num;
while (temp > 0)
{
p++;
temp /= 10;
}
for (i = 0;i < p;i++)
{
temp = num;
while (temp > 0)
{
indexNum = num % level / level2;
arr[indexNum]++;
level *= 10;
level2 *= 10;
temp /= 10;
}
}
for (j = 0; j < 10; j++)
{
printf("%d\n", arr[j]);
}
getch();
}
Here is simplified version of your program:
#include <stdio.h>
#include <math.h>
int main()
{
int i = 0, j = 0, temp = 0, indexNum = 0, num = 0, level = 10;
int arr[10] = {0};
num = 7766123;
temp = num;
if(0 == temp) arr[0] = 1; // Handle 0 input this way
while (temp > 0)
{
indexNum = temp % level;
arr[indexNum]++;
temp /= 10;
}
for (j = 0; j < 10; j++)
{
printf("%d\n", arr[j]);
}
return 0;
}
A few hints to help you:
What does arr[10] = { 0 } actually do?
When you calculate indexNum, you are dividing integers. What happens when the modulus is a one-digit number, and level2 is greater than 1?
It's probably easier to read the input into a string and count digit characters. Something like this (not tested):
std::map<char, int> count;
std::string input;
std::cin >> input;
for (auto iter = input.begin(); iter != input.end(); ++iter) {
if (*iter < 0 || *iter > 9)
break;
else
++count[*iter];
}
for (auto iter = count.begin(); iter != count.end(); ++iter) {
std::cout << *iter << '\n';
}
You need to get rid of your first for loop. Something more like:
#include <stdio.h>
#include <math.h>
using namespace std;
int main()
{
int j;
int temp;
int indexNum;
int arr[10] = { 0 };
int num;
int level = 10;
int level2 = 1;
printf("Please enter a digit number (upto 10 digits) \n");
scanf("%d", &num);
temp = num;
while (temp > 0)
{
indexNum = num % level / level2;
arr[indexNum]++;
level *= 10;
level2 *= 10;
temp /= 10;
}
for (j = 0; j < 10; j++)
{
printf("%d\n", arr[j]);
}
return 0;
}
Check the program below.
void count_digits(unsigned int a, int count[])
{
unsigned int last_digit = 0;
if (a == 0) {
count[0] = 1;
}
while (a != 0)
{
last_digit = a%10;
count[last_digit]++;
a = a/10;
}
}
int main()
{
int count[10]= {0};
unsigned int num = 1122345; /* This is the input, Change it as per your need */
int i = 0;
count_digits(num, count);
for (i = 0; i < 10; i++)
{
printf ("%d: -- %d\n", i, count[i]);
}
return 0;
}
The code is trying to find the largest palindrome made from the product of two 2-digit numbers. The answer is 91*99 = 9009 but I keep getting 990, which is not even a palindrome. I really appreciate the help!
#include <stdio.h>
int main()
{
int i = 10;
int j = 10;
int a = 0;
int b = 0;
int array[100] = {0};
int divider = 10;
int num;
int great;
int product;
int n;
int flag;
/*Loop through first 2 digit number and second 2 digit number*/
while (i<100)
{
while (j < 100)
{
product = i*j;
array [a] = product % 10;
n = product / divider;
while (n != 0)
{
a++;
num = n%10;
divider *=10;
array[a]=num;
n = product/divider;
}
flag = 0;
while (b<a)
{
if (array[b] != array[a])
{
flag = 1;
}
b++;
a--;
}
if (flag == 0)
{
great = product;
}
j++;
a = 0;
b = 0;
}
i++;
}
printf("The largest palindrome is %d \n", great);
return 0;
}
Here is a code snippet you can try.
#include <stdio.h>
void main()
{
int a = 1; // first integer
int b = 1; // second integer
int currentNumber;
int currentPalin; if a palindrome is found, its stored here
while (a<100){ //loop through the first number
while (b<100){ // loop through the second number
currentNumber = a*b;
if (currentNumber == reverse(currentNumber) ){ //check for palindrome
currentPalin = currentNumber;
}
b = b+1; //increment the second number
}
b = a; // you could have set b=1 but it would not be an efficient algorithm because
//some of the multiplication would occur twice. eg- (54*60) and (60*54)
a = a +1; //increment the first number
}
printf ("Largest palindrom is %d \n", currentPalin);
getchar();
}
// method for finding out reverse
int reverse(int n){
int reverse = 0;
while (n != 0)
{
reverse = reverse * 10;
reverse = reverse + n%10;
// when you divide a number by 10, the
//remainder gives you the last digit. so you are reconstructing the
//digit from the last
n = n/10;
}
return reverse;
}
Update:- As suggested by M Oehm, I have modified the code to make it more general.
#include <stdio.h>
void main()
{
int a = 1;
int b = 1;
int currentNumber;
int currentPalin=0;
while (a<100){
while (b<100){
currentNumber = a*b;
if (currentNumber == reverse(currentNumber) ){
if (currentNumber>currentPalin){
currentPalin = currentNumber;
}
}
b = b+1;
}
b = 1;
a = a +1;
}
if (currentPalin==0){
printf("No Palindrome exits in this range");
}
else {
printf ("Largest palindrome is %d \n", currentPalin);
}
getchar();
}
int reverse(int n){
int reverse = 0;
while (n != 0)
{
reverse = reverse * 10;
reverse = reverse + n%10;
n = n/10;
}
return reverse;
}
An alternative approach to solve the problem.
#include<stdio.h>
int reverse(int num)
{
int result = 0;
while( num > 0)
{
result = result * 10 + (num%10);
num/=10;
}
return result;
}
int main()
{
int last_best = 1;
int best_i=1;
int best_j = 1;
const int max_value = 99;
for( int i = max_value ; i > 0 ; --i)
{
for(int j = i ; j > 0 ; --j){
int a = i * j;
if( last_best > a )
break;
else if ( a == reverse(a) )
{
last_best = a;
best_i = i;
best_j = j;
}
}
}
printf("%d and %d = %d\n", best_i,best_j,last_best);
}
And it is quite simple to follow.
It seems that you do not reinitialize variables at the beginning of loop. They keeps values from previous iterations. For example, j and divider. Put
j = 10;
before starting "j" loop, i.e.:
j = 10;
while (j < 100) ...
The same for divider:
...
j = 10;
while (j < 100) {
divider = 10;
...
If you were using for loops you would avoid this problem naturally:
for(i=10; i<100; i++) {
for(j=10; j<100; j++) {
...
}
}