I have to write a C program that multiplies numbers from 1 to N.
N is scanned. Before multiplication, I have to increase each number by 2.
For example: N = 3 => (1+2)(2+2)(3+2) = 60
I have to only use while loop and print and scan function.
Example program:
Enter the value of N: 4
The result of multiplication: 360
This is my code and I am not sure what is wrong with this. Please help.
#include <stdio.h>
int N;
int count=1, ii, result;
printf("Enter the value of N:");
scanf("%d", &N);
while (count<=N)
{
count ii = count + 2;
ii = ii * ii ; //three
count++;
}
result = ii;
printf("The result of multiplication: %d", result);
return 0;
}
If you're looking for that series as a sum:
const int N = 3;
int c = 1;
for (int i = 1; i <= N; ++i) {
c *= (i + 2);
}
Or in a more C-esque form:
const int N = 3;
int c = 1;
for (int i = 0; i < N; ++i) {
c *= (i + 1 + 2);
}
int main()
{
int N;
int count=1, ii = 1, result;
printf("Enter the value of N:");
scanf("%d", &N);
while (count<=N)
{
ii = ii * ( count + 2 };
count++;
}
result = ii;
printf("The result of multiplication: %d", result);
return 0;
}
Related
I'm not sure why I'm getting inf values when plugging in a 3 equation answer, another set of eyes on the equation loop would be useful, when I use a single equation the number of iterations is correct but when it's more than that the numbers multiply to inf.
Inputs for the code I used
Enter the Total Number of Equations: 3
Enter Allowed Error: 0.5
Enter the Co-Efficients
Matrix[1][1] = 1
Matrix[1][2] = 2
Matrix[1][3] = 3
Matrix[1][4] = 4
Matrix[2][1] = 2
Matrix[2][2] = 3
Matrix[2][3] = 4
Matrix[2][4] = 5
Matrix[3][1] = 3
Matrix[3][2] = 4
Matrix[3][3] = 5
Matrix[3][4] = 6
#include<stdio.h>
#include<math.h>
int main()
{
int count, t, limit;
float temp, error, a, sum = 0;
float matrix[10][10], y[10], allowed_error;
printf("\nEnter the Total Number of Equations:\t");
scanf("%d", &limit);
printf("Enter Allowed Error:\t");
scanf("%f", &allowed_error);
printf("\nEnter the Co-Efficients\n");
for(count = 1; count <= limit; count++)
{
for(t = 1; t <= limit + 1; t++)
{
printf("Matrix[%d][%d] = ", count, t);
scanf("%f", &matrix[count][t]);
}
}
for(count = 1; count <= limit; count++)
{
y[count] = 0;
}
do
{
a = 0;
for(count = 1; count <= limit; count++)
{
sum = 0;
for(t = 1; t <= limit; t++)
{
if(t != count)
{
sum = sum + matrix[count][t] * y[t];
}
}
temp = (matrix[count][limit + 1] - sum) / matrix[count][count];
error = fabs(y[count] - temp);
if(error > a)
{
a = error;
}
y[count] = temp;
printf("\nY[%d]=\t%f", count, y[count]);
}
printf("\n");
}
while(a >= allowed_error);
printf("\n\nSolution\n\n");
for(count = 1; count <= limit; count++)
{
printf("\nY[%d]:\t%f", count, y[count]);
}
return 0;
}
Your code is correct. The issue is that Gauss-Seidel method does not always converge. The convergence criteria is that the matrix A must be either:
symmetric positive-definite
strictly or irreducibly diagonally dominant
The input matrix you used is neither symmetric, nor diagonally-dominant. Hence, the method fails to converge to a solution.
I am trying to print the series but whenever I set the range (input given by me) above 407. I only get the output till 407. However, when I set the range below 407 it gives me the result according to the input I have given. Can anybody tell me what I'm doing wrong?
I used an online compiler (www.onlinegdb.com) to write my code.
Here is the code.
#include<stdio.h>
#include<stdlib.h>
int
main ()
{
int m, n;
printf
("Enter two numbers to find the Armstrong numbers that lie between them.\n");
scanf ("%d%d", &m, &n);
system("clear");
if(m>n)
{
m = m + n;
n = m - n;
m = m - n;
}
for (; m < n; m++)
{
int i = m + 1, r, s = 0, t;
t = i;
while (i > 0)
{
r = i % 10;
s = s + (r * r * r);
i = i / 10;
}
if (t == s)
printf ("%d ", t);
}
return 0;
}
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Try this code!!!
#include <math.h>
#include <stdio.h>
int main() {
int low, high, number, originalNumber, rem, count = 0;
double result = 0.0;
printf("Enter two numbers(intervals): ");
scanf("%d %d", &low, &high);
printf("Armstrong numbers between %d and %d are: ", low, high);
// swap numbers if high < low
if (high < low) {
high += low;
low = high - low;
high -= low;
}
// iterate number from (low + 1) to (high - 1)
// In each iteration, check if number is Armstrong
for (number = low + 1; number < high; ++number) {
originalNumber = number;
// number of digits calculation
while (originalNumber != 0) {
originalNumber /= 10;
++count;
}
originalNumber = number;
// result contains sum of nth power of individual digits
while (originalNumber != 0) {
rem = originalNumber % 10;
result += pow(rem, count);
originalNumber /= 10;
}
// check if number is equal to the sum of nth power of individual digits
if ((int)result == number) {
printf("%d ", number);
}
// resetting the values
count = 0;
result = 0;
}
return 0;
}
Try this code :
#include <stdio.h>
#include <math.h>
int main()
{
int start, end, i, temp1, temp2, remainder, n = 0, result = 0;
printf(“Enter start value and end value : “);
scanf(“%d %d”, &start, &end);
printf(“\nArmstrong numbers between %d an %d are: “, start, end);
for(i = start + 1; i < end; ++i)
{
temp2 = i;
temp1 = i;
while (temp1 != 0)
{
temp1 /= 10;
++n;
}
while (temp2 != 0)
{
remainder = temp2 % 10;
result += pow(remainder, n);
temp2 /= 10;
}
if (result == i) {
printf(“%d “, i);
}
n = 0;
result = 0;
}
printf(“\n”);
return 0;
}
Goldbach's conjecture states that every even integer over 4 is the sum of two primes, I am writing a program in C to find these pairs. To do this it first finds all the primes less than a user given number. I have a for loop to iterate from 4 to the user given number and find the pairs within the loop body. When that loop gets to about around 40, suddenly jumps back down by about 30 and then continues to iterate up (with user input 50 it jumped from 38 to 9, with input 60 it jumped from 42 to 7). I can't figure out why this is happening. Here is my code:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <sys/types.h>
#include <unistd.h>
struct pair{
int a;
int b;
}pair_t;
int main(){
int N;
int numPrimes = 1;
int *primes = malloc(100*sizeof(int));
int isPrime = 1;
primes[0] = 2;
int timesRealloc = 0;
int availableSlots = 100;
printf("Please enter the largest even number you want to find the Goldbach pair for: \n");
scanf("%d", &N);
struct pair pairs[N/2 + 4];
int j = 0;
int i;
for (i = 3; i <= N; i+=2){
j = 0;
isPrime = 1;
while (primes[j] <= sqrt(i)) {
if (i%primes[j] == 0) {
isPrime = 0;
break;
}
j++;
}
if (isPrime == 1){
primes[numPrimes] = i;
numPrimes++;
}
if (availableSlots == numPrimes){
timesRealloc++;
availableSlots += 100;
primes = realloc(primes, availableSlots*sizeof(int));
}
}
printf("The largest prime I found was %d\n", primes[(numPrimes-1)]);
int k;
for (i=4; i<=N; i+=2){
printf("i is %d, N is %d\n", i, N);
if (i > N){ break; }
for (j=0; j<numPrimes; j++){
for (k=0; k<numPrimes; k++){
int sum = primes[j] + primes[k];
if(sum == i){
pairs[i].a = primes[j];
pairs[i].b = primes[k];
}
}
}
}
for (i=4; i<=N; i+=2){
printf("%d is the sum of %d and %d\n", i, pairs[i].a, pairs[i].b);
}
return 0;
}
You attempt to be space efficient by compressing the pairs array to just hold every other (even) number and start from 4 instead of zero. However, you miscalculate its size and then when you go to use it, you treat it like it hasn't been compressed and that there's a slot for every natural number.
The code suffers from having the prime array calculation in main() along with the other code, this is best separated out. And when it looks for pairs, it doesn't quit when it finds one, nor when it starts getting sums greater than the target. My rework below attempts to address all of these issues:
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <stdbool.h>
#define INITIAL_SLOTS (100)
struct pair {
int a;
int b;
} pair_t;
int compute_primes(int limit, unsigned **primes, int size) {
int numPrimes = 0;
(*primes)[numPrimes++] = 2;
for (int i = 3; i <= limit; i += 2) {
bool isPrime = true;
for (int j = 0; (*primes)[j] <= i / (*primes)[j]; j++) {
if (i % (*primes)[j] == 0) {
isPrime = false;
break;
}
}
if (isPrime) {
(*primes)[numPrimes++] = i;
}
if (numPrimes == size) {
size *= 2;
*primes = realloc(*primes, size * sizeof(unsigned));
}
}
return numPrimes;
}
int main() {
int N;
printf("Please enter the largest even number you want to find the Goldbach pair for: \n");
scanf("%d", &N);
unsigned *primes = calloc(INITIAL_SLOTS, sizeof(unsigned));
int numPrimes = compute_primes(N, &primes, INITIAL_SLOTS);
printf("The largest prime I found was %d\n", primes[numPrimes - 1]);
struct pair pairs[(N - 4) / 2 + 1]; // compressed data structure
for (int i = 4; i <= N; i += 2) {
int offset = (i - 4) / 2; // compressed index
bool found = false;
for (int j = 0; ! found && j < numPrimes; j++) {
for (int k = 0; ! found && k < numPrimes; k++) {
int sum = primes[j] + primes[k];
if (sum == i) {
pairs[offset].a = primes[j];
pairs[offset].b = primes[k];
found = true;
} else if (sum > i) {
break;
}
}
}
}
for (int i = 4; i <= N; i += 2) {
int offset = (i - 4) / 2; // compressed index
printf("%d is the sum of %d and %d\n", i, pairs[offset].a, pairs[offset].b);
}
free(primes);
return 0;
}
OUTPUT
> ./a.out
Please enter the largest even number you want to find the Goldbach pair for:
10000
The largest prime I found was 9973
4 is the sum of 2 and 2
6 is the sum of 3 and 3
8 is the sum of 3 and 5
10 is the sum of 3 and 7
12 is the sum of 5 and 7
14 is the sum of 3 and 11
...
9990 is the sum of 17 and 9973
9992 is the sum of 19 and 9973
9994 is the sum of 53 and 9941
9996 is the sum of 23 and 9973
9998 is the sum of 31 and 9967
10000 is the sum of 59 and 9941
>
#include <stdio.h>
int main()
{
int i; //counter for the loop
int n; //integer
int series;
printf("Enter an integer number: ");
scanf("%d" , &n);
for(i = 1; i <= n; i++)
{
if (i % 2 == 0)
(series -= i * i);
else
(series += i * i);
}
printf("The value of the series is: %d\n" , series);
return 0;
}
So the the loop is just a basic for loop, using I as the counter for as long as it is less than or equal to n
the series that I have to replicate adds odd numbers and subtracts even numbers so the if condition tests if the number is even or odd. The program compiles fine but when I enter the integer as 5 the sum of the series should be 15, however my program gives the sum 32779. Any help on fixing my program would be appreciated.
you didn't initialize series, so it's a random value in the beginning of the calculation.
#include <stdio.h>
int main()
{
int i = 0; //counter for the loop
int n = 0; //integer
int series = 0;
printf("Enter an integer number: ");
scanf("%d" , &n);
for(i = 1; i <= n; i++)
{
if (i % 2 == 0)
(series -= i * i);
else
(series += i * i);
}
printf("The value of the series is: %d\n" , series);
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.