I want to make a code were you find all the even numbers between N number of cases(y). The next y lines will contain a n number (1<=n1<=100). For each line I want to find the even numbers between these. So for example:
input:
2 (number of cases; 1<=y<=10)
1
7
Output:
No even numbers
2 4 6
If there is no even numbers between them then print "No even numbers" for example:
So what I've made up until now is this:
#include <stdio.h>
int main()
{
int n1, n2, i, j, p, y;
printf("number of intervals: ");
scanf("%d", &y);
for(j=1; j<=y; j++)
{
scanf("%d", &n1);
for(i=1;i<=n1; i++)
{
p=i%2;
if(p==0)
printf(" %d", i);
}
return 0;
}
}
The thing is that I dont know how to implement the number of intervals to the code, it only works with two intervals.
Its always a good idea to make a function if you want to do similar thing with different values.You can make a function and call that function as many time as you need.For example
void printInterval(int n1, int n2){ //function will print all even
for(i=n1;i<=n2; i++)//number between n1 and n2 (both inclusive)
{
p=i%2;
if(p==0)
printf(" %d", i);
}
}
Related
How can I get output in this code? As you can see the question for the code which I have written in comments. This is written in C.
/*To print prime numbers from n1 to n2 where n1 and n2 are input by user and n1<n2*/
//please solve this code, i am stuck
#include <stdio.h>
#include <conio.h>
void main()
{
int n1, n2, i, j;
printf("Enter two numbers");
scanf("%d\t%d\n", &n1, &n2);
printf("The prime numbers in betwn %d and %d are:\n", n1, n2);
for (i = n1; i <= n2; i++)
{
for (j = 2; j < i; j++)
{
if (i % 2 == 0)
{
continue;
}
}
if (i = j)
{
printf("%d\t", i);
}
}
getch();
}
scanf("%d\t%d\n", &n1, &n2);
Issue seems here. Input needs to be provided in the same way as specified in the format of scanf(). I suggest changing it to the following for simplicity:
scanf("%d %d", &n1, &n2);
Another thing: if (i = j) , this should be comparison operator instead of assignment.
Since you are trying to print prime numbers in a range, the logic/approach seems incorrect as well.
To add more detail:
First, l agree with dev7060 and thanks to him. There are two aspects which you should pay attention to:
1) %d\t%d\n means you should input three parameters into the data flow. You can see this which l have tested in my side.
So please try this like dev7060 said:
scanf("%d%d", &n1, &n2);
And note when you input one parameter, please first hit a space bar and then input the second parameter. %d%d can grab two digits into the input stream before the entry by any space character, such as the TAB key or space bar, or the enter key. So when you enter parameters, you can get them by typing an interval character between them.
2) i=j means an assignment operation rather than a comparison operation and it always returns true.
You should use if(i==j).
Please refer to this:
#include <iostream>
#include <stdio.h>
#include <conio.h>
int main()
{
int n1, n2, i, j;
printf("Enter two numbers");
scanf("%d%d", &n1, &n2);
printf("The prime numbers in betwn %d and %d are:\n", n1, n2);
for (i = n1; i <= n2; i++)
{
for (j = 2; j < i; j++)
{
if (i % 2 == 0)
{
continue;
}
}
if (i == j)
{
printf("%d\t", i);
}
}
getch();
}
In addition, when you face these issues in VS:
error C4996: 'scanf': This function or variable may be unsafe. error
error C4996: 'getch': The POSIX name for this item is deprecated.
These are compiler errors and you should use scanf_s() instead of scanf() and use _getch() instead of getch(). You can refer to this.
I am learning C on my own with a book and I cannot for the life of me figure out how to solve this exercise. I'm obviously looking at it in the wrong way or something. Here is an explanation below.
Listed below are some functions and the main function at the bottom. This program is compiled to generate a certain number of random numbers and determine the min and the max of the random numbers. If you copy and paste this code, you will see how it works. Anyways, an exercise asks me to go to the function "prn_random_numbers()" and change the for loop from "for (i = 1; i < k; ++i)" to for (i = 2; i <= k; ++i). This causes the first line format to print incorrectly. The exercise is to further modify the program in the body of the for loop to get the output to be formatted correctly.
To sum it up, the "prn_random_numbers()" function is written to print out 5 random numbers before moving to the next line. Hence the" i % 5" if statement. Now, for some reason, when you make the slight adjustment to the for loop, as the exercise asks above, it causes the first line to only print 4 numbers before moving to the next line. I have tried a number of things, including trying to force it to print the 5th number, but it only duplicated one of the random numbers. I even tried "i % 4" to see if it would print 4 numbers for each row, but it only prints 3 numbers for the first row instead of 4! So it always prints one less number on the first line than it is supposed to. I have n clue why it is doing that and the book does not give an exercise. Do you have any idea?
Bear with me if you think this is a stupid question. I am just learning on my own and I want to make sure I have a good foundation and understand everything as I learn it, before moving forward. I appreciate any help or advice!
prn_random_numbers(k) /* print k random numbers */
int k;
{
int i, r, smallest, biggest;
r = smallest = biggest = rand();
printf("\n%12d", r);
for (i = 1; i < k; ++i)
{
if (i % 5 == 0)
printf("\n");
r = rand();
smallest = min(r, smallest);
biggest = max(r, biggest);
printf("%12d", r);
}
printf("\n\n%d random numbers printed.\n", k);
printf("Minimum:%12d\nMaximum:%12d\n", smallest, biggest);
}
int main()
{
int n;
printf("Some random numbers are to be printed.\n");
printf("How many would you like to see? ");
scanf("%d", &n);
while (n < 1)
{
printf("ERROR! Please enter a positive integer.\n");
printf("How many would you like to see? ");
scanf("%d", &n);
}
prn_random_numbers(n);
return (EXIT_SUCCESS);
}
the following proposed code:
properly initializes the random number generator
cleanly compiles
properly checks for and handles errors
performs the desired functionality
avoids having to list instructions twice
follows the axiom: Only one statement per line and (at most) one variable declaration per statement.
does not use undefined functions like: max() and min()
and now the proposed code:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
void prn_random_numbers(int k)
{
int count = 1;
int r;
int smallest;
int biggest;
r = smallest = biggest = rand();
printf("\n%12d", r);
for ( int i = 2; i <= k; i++, count++)
{
if (count % 5 == 0)
{
count = 0;
printf("\n");
}
r = rand();
smallest = (r < smallest)? r : smallest;
biggest = (r > biggest)? r : biggest;
printf("%12d", r);
}
printf("\n\n%d random numbers printed.\n", k);
printf("Minimum:%12d\nMaximum:%12d\n", smallest, biggest);
}
int main( void )
{
int n;
srand( (unsigned)time( NULL ) );
do
{
printf("Please enter a positive integer, greater than 0.\n");
printf("How many would you like to see? ");
if( scanf("%d", &n) != 1 )
{
fprintf( stderr, "scanf for number of random numbers failed\n" );
exit( EXIT_FAILURE );
}
} while( n < 1 );
prn_random_numbers(n);
// in modern C, if the returned value from `main()` is 0 then no `return 0;` statement needed
}
a typical run, no input problems is:
Please enter a positive integer, greater than 0.
How many would you like to see? 20
98697066 2110217332 1247184349 421403769 1643589269
1440322693 985220171 1915371488 1920726601 1637143133
2070012356 541419813 1708523311 1237437366 1058236022
926434075 1422865093 2113527574 626328197 1618571881
20 random numbers printed.
Minimum: 98697066
Maximum: 2113527574
Try to use a debugger to solve your problem, it's easy to use and really helpfull :)
SOLUTION:
Your i variable don't count the number of numbers because it is initialize at 1 (in the for statement), so you need to declare a new variable to count properly.
If you have still a problem:
void prn_random_numbers(int k)
{
int count = 1;
int i, r, smallest, biggest;
r = smallest = biggest = rand();
printf("\n%12d", r);
for (i = 2; i <= k; i++, count++) {
if (count % 5 == 0) {
count = 0;
printf("\n");
}
r = rand();
smallest = min(r, smallest);
biggest = max(r, biggest);
printf("%12d", r);
}
printf("\n\n%d random numbers printed.\n", k);
printf("Minimum:%12d\nMaximum:%12d\n", smallest, biggest);
}
#include <stdio.h>
#include <conio.h>
int getn(int n, int i);
int main()
{
int n, i;
getn(n, i);
getch();
return 0;
}
int getn(int n, int i)
{
int even = 0;
int odd = 1;
int avg;
printf("Enter ten integers: \n");
for (i = 1 ; i <= 10 ; i++)
{
printf("Integer %d: ", i);
scanf("%d", &n);
if ( n % 2 == 0 )
{
even = even + n;
}
else
{
odd = odd * n;
}
}
avg = even / 10;
printf("\n\nAverage of even numbers: %d", avg);
printf("\nProduct of odd numbers: %d", odd);
}
It seems the even calculations worked but when it comes to odd it gives the wrong answer. Please help
Our instructor wants us to use looping or iterations. No arrays. Please help me
First, your C code needs some correction:
at least give the prototype of getn before using it
getn is defined to return an int and doesn't return anything. Either replace int with void or return a value.
Second,
Your code computes the product of ten numbers, if this product is too big, it cannot be store as-is in an int. For example, it works well if you enter ten times number 3, the result is 59049, but if you enter ten times number 23, it will answer 1551643729 which is wrong because 23^10=41426511213649 but that can't be stored in an int. This is known as arithmetic overflow.
Your average is bad, because you sum ints, but the average is (in general) a rational number (average(2,3)=2.5 isn't it ?). So double avg = out/10.0; (means compute a floating division) and printf("Average %f\n",avg); would be better.
I'm a newbie!
I'm supposed to get 2 integers from the user, and print the result(sum of all numbers between those two integers).
I also need to make sure that the user typed the right number.
The second number should be bigger than the first one.
And if the condition isn't fulfilled, I have to print "The second number should be bigger than the first one." and get the numbers from the user again until the user types right numbers that meet the condition.
So if I programmed it right, an example of the program would be like this.
Type the first number(integer) : 10
Type the second number(integer) : 1
The second number should be bigger than the first one.
Type the first number(integer) : 1
Type the second number(integer) : 10
Result : 55
End
I think that I have to make two loops, but I can't seem to figure out how.
My English is limited, to help your understanding of this quiz, I'll add my flowchart below.
I tried many different ways I can think of, but nothing seems to work.
This is the code that I ended up with now.
But this doesn't work either.
#include <stdio.h>
void main(void)
{
int a = 0;
int b = 0;
int total_sum = 0;
printf("Type the first number : \n");
scanf("%d", &a);
printf("Type the second number : \n");
scanf("%d", &b);
while (a > b) {
printf("The second number should be bigger than the first one.\n");
printf("Type the first number : \n");
scanf("%d", &a);
printf("Type the second number : \n");
scanf("%d", &b);
}
while (a <= b) {
total_sum += a;
a++;
}
printf("Result : \n", total_sum);
}
Instead of using loop to sum the numbers, we can use mathematical formula.
Sum of first N integers= N*(N+1)/2
#include <stdio.h>
int main(void)
{
int a = 0;
int b = 0;
int sum;
//Run infinite loop untill a>b
while(1)
{
printf("Type the first number : ");
scanf("%d", &a);
printf("Type the second number : ");
scanf("%d", &b);
if(a>b)
{
printf("The second number should be bigger than the first one.\n");
}
else
{
break;
}
}
//Reduce comlexity of looping
sum=((b*(b+1))-(a*(a-1)))/2;
printf("Result : %d " , sum);
return 0;
}
After corrections your code should run. The community has pointed out many mistakes in your code. Here's an amalgamated solution:
#include <stdio.h>
int main(void)
{
int a = 0;
int b = 0;
int correctInput=0;
int total_sum = 0;
do
{
printf("Type the first number : \n");
scanf("%d", &a);
printf("Type the second number : \n");
scanf("%d", &b);
if(a<b)
correctInput=1;
else
printf("The second number should be bigger than the first one.\n");
}
while (correctInput ==0) ;
while (a <= b) {
total_sum += a;
a++;
}
printf("Result : %d \n" , total_sum);
return 0;
}
Factorials are used frequently in probability problems. The factorial of a positive integer n (written n! and pronounced "n factorial") is equal to the product of the positive integers from 1 to n: n! = 1 x 2 x 3 x x n Write a program that takes as input an integer n and computes n!.
Even though this question has been asked a million times I just haven't found an answer that actually helps my case, or I simply can't see the solution.
I've been given the task to make a program that takes in a whole number and counts how many times each digit appears in it and also not showing the same information twice. Since we're working with arrays currently I had to do it with arrays of course so since my code is messy due to my lack of knowledge in C I'll try to explain my thought process along with giving you the code.
After entering a number, I took each digit by dividing the number by 10 and putting those digits into an array, then (since the array is reversed) I reversed the reverse array to get it to look nicer (even though it isn't required). After that, I have a bunch of disgusting for loops in which I try to loop through the whole array while comparing the first element to all the elements again, so for each element of the array, I compare it to each element of the array again. I also add the checked element to a new array after each check so I can primarily check if the element has been compared before so I don't have to do the whole thing again but that's where my problem is. I've tried a ton of manipulations with continue or goto but I just can't find the solution. So I just used **EDIT: return 0 ** to see if my idea was good in the first place and to me it seems that it is , I just lack the knowledge to go back to the top of the for loop. Help me please?
// With return 0 the program stops completely after trying to check the digit 1 since it's been checked already. I want it to continue checking the other ones but with many versions of putting continue, it just didn't do the job. //
/// Tried to make the code look better. ///
#include <stdio.h>
#define MAX 100
int main()
{
int a[MAX];
int b[MAX];
int c[MAX];
int n;
int i;
int j;
int k;
int counter1;
int counter2;
printf("Enter a whole number: ");
scanf("%i",&n);
while (1)
{
for (i=0,counter1=0;n>10;i++)
{
a[i] = n%10;
n=n/10;
counter1+=1;
if (n<10)
a[counter1] = n;
}
break;
}
printf("\nNumber o elements in the array: %i", counter1);
printf("\nElements of the array a:");
for (i=0;i<=counter1;i++)
{
printf("%i ",a[i]);
}
printf("\nElements of the array b:");
for (i=counter1,j=0;i>=0;i--,j++)
{
b[j] = a[i];
}
for (i=0;i<=counter1;i++)
{
printf("%i ",b[i]);
}
for (i=0;i<=counter1;i++)
{
for(k=0;k<=counter1;k++)
{
if(b[i]==c[k])
{
return 0;
}
}
for(j=0,counter2=0; j<=counter1;j++)
{
if (b[j] == b[i])
{
counter2+=1;
}
}
printf("\nThe number %i appears %i time(s)", b[i], counter2);
c[i]=b[i];
}
}
The task at hand is very straightforward and certainly doesn't need convoluted constructions, let alone goto.
Your idea to place the digits in an array is good, but you increment counter too early. (Remember that arrays in C start with index 0.) So let's fix that:
int n = 1144526; // example number, assumed to be positive
int digits[12]; // array of digits
int ndigit = 0;
while (n) {
digits[ndigit++] = n % 10;
n /= 10;
}
(The ++ after ndigit will increment ndigit after using its value. Using it as array index inside square brackets is very common in C.)
We just want to count the digits, so reversing the array really isn't necessary. Now we want to count all digits. We could do that by counting all digits when we see then for the first time, e.g. in 337223, count all 3s first, then all 7s and then all 2s, but that will get complicated quickly. It's much easier to count all 10 digits:
int i, d;
for (d = 0; d < 10; d++) {
int count = 0;
for (i = 0; i < ndigit; i++) {
if (digit[i] == d) count++;
}
if (count) printf("%d occurs %d times.\n", d, count);
}
The outer loop goes over all ten digits. The inner loop counts all occurrences of d in the digit array. If the count is positive, write it out.
If you think about it, you can do better. The digits can only have values from 0 to 9. We can keep an array of counts for each digit and pass the digit array once, counting the digits as you go:
int count[10] = {0};
for (i = 0; i < ndigit; i++) {
count[digit[i]]++;
}
for (i = 0; i < 10; i++) {
if (count[i]) printf("%d occurs %d times.\n", i, count[i]);
}
(Remember that = {0} sets the first element of count explicitly to zero and the rest of the elements implicitly, so that you start off with an array of ten zeroes.)
If you think about it, you don't even need the array digit; you can count the digits right away:
int count[10] = {0};
while (n) {
count[n % 10]++;
n /= 10;
}
for (i = 0; i < 10; i++) {
if (count[i]) printf("%d occurs %d times.\n", i, count[i]);
}
Lastly, a word of advice: If you find yourself reaching for exceptional tools to rescue complicated code for a simple task, take a step back and try to simplify the problem. I have the impression that you have added more complicated you even you don't really understand instead.
For example, your method to count the digits is very confused. For example, what is the array c for? You read from it before writing sensible values to it. Try to implement a very simple solution, don't try to be clever at first and go for a simple solution. Even if that's not what you as a human would do, remeber that computers are good at carrying out stupid tasks fast.
I think what you need is a "continue" instead of a return 0.
for (i=0;i<=counter1;i++) {
for(k=0;k<=counter1;k++) {
if(b[i]==c[k]) {
continue; /* formerly return 0; */
}
for(j=0,counter2=0; j<=counter1;j++)
if (b[j] == b[i]){
counter2+=1;
}
}
Please try and see if this program can help you.
#include <stdio.h>
int main() {
unsigned n;
int arr[30];
printf("Enter a whole number: ");
scanf("%i", &n);
int f = 0;
while(n)
{
int b = n % 10;
arr[f] = b;
n /= 10;
++f;
}
for(int i=0;i<f;i++){
int count=1;
for(int j=i+1;j<=f-1;j++){
if(arr[i]==arr[j] && arr[i]!='\0'){
count++;
arr[j]='\0';
}
}
if(arr[i]!='\0'){
printf("%d is %d times.\n",arr[i],count);
}
}
}
Test
Enter a whole number: 12234445
5 is 1 times.
4 is 3 times.
3 is 1 times.
2 is 2 times.
1 is 1 times.
Here is another offering that uses only one loop to analyse the input. I made other changes which are commented.
#include <stdio.h>
int main(void)
{
int count[10] = { 0 };
int n;
int digit;
int elems = 0;
int diff = 0;
printf("Enter a whole number: ");
if(scanf("%d", &n) != 1 || n < 0) { // used %d, %i can accept octal input
puts("Please enter a positive number"); // always check result of scanf
return 1;
}
do {
elems++; // number of digits entered
digit = n % 10;
if(count[digit] == 0) { // number of different digits
diff++;
}
count[digit]++; // count occurrence of each
n /= 10;
} while(n); // do-while ensures a lone 0 works
printf("Number of digits entered: %d\n", elems);
printf("Number of different digits: %d\n", diff);
printf("Occurrence:\n");
for(n = 0; n < 10; n++) {
if(count[n]) {
printf(" %d of %d\n", count[n], n);
}
}
return 0;
}
Program session:
Enter a whole number: 82773712
Number of digits entered: 8
Number of different digits: 5
Occurrence:
1 of 1
2 of 2
1 of 3
3 of 7
1 of 8