omitting last comma when printing a list - c

I want to show prime numbers between two numbers like this 2,5,7,11
but it shows like this 2,5,7,11, there is an extra ",".
#include <stdio.h>
int main()
{
int n1,n2,f,i,j;
scanf("%d %d", &n1, &n2);
for(i=n1; i<n2; ++i)
{
f=0;
for(j=2; j<=i/2; ++j)
{
if(i%j==0)
{
f=1;
break;
}
}
if(f==0)
if(i!=1)
printf("%d,",i);
}
return 0;
}

Answering the question but not accounting for the point raised by #Bathsheeba:
#include <stdio.h>
int main()
{
int n1,n2,f,i,j;
scanf("%d %d", &n1, &n2);
int itemCount = 0; // NEW
for(i=n1; i<n2; ++i)
{
f=0;
for(j=2; j<=i/2; ++j)
{
if(i%j==0)
{
f=1;
break;
}
}
if (f == 0 && i != 1) // TESTS COMBINED
{
if (itemCount++ > 0) putchar(','); // HERE
printf("%d",i); // COMMA REMOVED
}
}
printf("\n"); // newline at the end
return 0;
}
The only way to really remove a comma after you've added it is if you're building a buffer at runtime - which is a reasonable approach - so here we have to only generate a comma when we need it, before all but the first item.

Related

C program to insert elements into an array until user inputs a 0 or less number

I'm trying to make a C program to insert elements into an array until user inputs a 0 or less number, as the title says. But when I print the array out, it doesn't show the numbers I inputted. I have tried using a while as well as do-while loops but without success.
#include <stdio.h>
int main() {
int data[100];
int i;
for (i = 0; i < 100; i++) {
printf("Input your number:\n");
scanf("%d", &data[i]);
if (data[i] <= 0) {
break;
}
}
printf("Your array:");
int n = sizeof(data[i]);
for (int i = 0; i < n; i++) {
printf("%d ", &data[i]);
}
}
Try this:
#include <stdio.h>
int main() {
int data[100];
int i;
int counter = 0;
for (i = 0; i < 100; i++) {
printf("Input your number:\n");
scanf("%d", &data[i]);
counter++;
if (data[i] <= 0) {
break;
}
}
printf("Your array:");
for (int j = 0; j < counter - 1; j++) {
printf("%d ", data[j]);
}
}
The problem was that you had printf("%d ", &data[i]); instead of printf("%d ", data[i]);.
And also you've trying to get the sizeof() of an element data[i], not the size of the whole array. That's why there's counter in my code.
int n = sizeof(data[i]);
this is wrong, you want
int n = i;
sizeof(data[i]) gives you the size of an int (4 on my machine)
On the other hand, you need to check the result of scanf, if a bad input is entered do not increment the counter, something like:
int i = 0;
while (i < 100)
{
int res = scanf("%d", &data[i]);
if (res == EOF)
{
break;
}
if (res == 1)
{
if (data[i] <= 0)
{
break;
}
i++;
}
else
{
// Sanitize stdin
int c;
while ((c = getchar()) != '\n');
}
}
Finally, scanf wants a pointer to the object, but this is not the case of printf:
printf("%d ", &data[i])
should be
printf("%d ", data[i])

URI 1101 Sequence of Numbers and Sum

#include <stdio.h>
int main() {
int M,N,i=0,sum=0;
while(M>0 || N>0){
scanf("%d%d",&M,&N);
if(M<=0 || N<=0){
break;
}
else if(M==N){ printf("%d Sum=%d\n",N,M); }
else if(M<N){
for(i=M; i<=N; i++){
printf("%d ",i);
sum+=i;
}
printf("Sum=%d\n",sum);
sum=0;
}
else if(M>N){
for(i=N; i<=M; i++){
printf("%d ",i);
sum+=i;
}
printf("Sum=%d\n",sum);
sum=0;
}
}
return 0;
}
what is wrong with this code? URI judge saying 100% wrong answer but I tried all the test cases and it passed in those cases
I'm not sure, but before while loop you should get scanf("%d%d",&M,&N); one time.
Because the m and n is not defined.
Like this way :
scanf("%d%d",&M,&N);
while(M>0 || N>0){
scanf("%d%d",&M,&N);
if(M<=0 || N<=0){
break;
}
...

How to remove the last comma in comma separated prime numbers within a range?

I have the code for finding prime numbers within a range.
The problem is to remove the last comma.
#include<stdio.h>
int main()
{
int a,b,i,x,c,f=1;
scanf("%d%d",&a,&b);
for(x=a;x<=b;(x++,f=0))
{
for(i=2;i<x;i++)
{
if(x%i==0)
{
f=1;
}
}
if(f==0)
printf("%d,",x);
}
}
But the output contains an extra comma in the last.
For example
2,3,5,7,
whereas the expected output is
2,3,5,7
Instead of flag you can decide directly what you want to print between numbers
And note that you can break out of the internal loop as soon as f is set to 1
#include<stdio.h>
int main()
{
int a,b,i,x,c,f=1;
const char* delim = "";
scanf("%d%d",&a,&b);
for(x=a; x<=b; (x++,f=0))
{
for(i=2; i<x; i++)
{
if(x%i==0)
{
f=1;
break; //no need to continue the checking
}
}
if(f==0) {
printf("%s%d",delim,x);
delim = ", ";
}
}
putchar('\n');
}
#include<stdio.h>
int main()
{
int a,b,i,x,c,f=1;
char backspace = 8;
scanf("%d%d",&a,&b);
for(x=a;x<=b;(x++,f=0))
{
for(i=2;i<x;i++)
{
if(x%i==0)
{
f=1;
}
}
if(f==0)
printf("%d,",x);
}
printf("\b"); // or printf("%c", backspace);
}
Add another flag, just a simple counter that tells you if you are printing the first time then check the flag to decide what to print, e.g.
#include<stdio.h>
int main()
{
int a,b,i,x,c,first=0,f=1;
scanf("%d%d",&a,&b);
for(x=a;x<=b;(x++,f=0))
{
for(i=2;i<x;i++)
{
if(x%i==0)
{
f=1;
}
}
if(f==0)
{
if(first==0){
printf("%d",x);
}else{
printf(",%d",x);
}
first++
}
}
}
Use a flag to detect the first occurrence of printf() and print the first number as such without any ,. For consecutive number printing precede with ,
#include<stdio.h>
int main()
{
int a,b,i,x,c,f=1,flag=0;//Flag to mark first occurrence
scanf("%d%d",&a,&b);
for(x=a;x<=b;(x++,f=0))
{
for(i=2;i<x;i++)
{
if(x%i==0)
{
f=1;
break;// Once the condition fails can break of the for loop as it fails for the prime number condition at the first case itself
}
}
if(f==0)
{
if(flag==0)
{//Check if it is first time
printf("%d",x);
flag = 1;//If so print without ',' and set the flag
}
else
printf(",%d",x);// On next consecutive prints it prints using ','
}
}
}
This method also avoids the , when only one number is printed.
Eg: When input is 2 and 4. It prints just 3 and not 3,
Simply you need odd number best practice for minimum loop is given below;
#include<stdio.h>
int main()
{
int a,b,i,x,c,f=1;
scanf("%d%d",&a,&b);
while (a < b)
{
if ( (a%2) == 1) {
printf("%d", a);
if ( (a + 1) < b && (a + 2) < b)
printf(",");
}
a = a + 1;
}
}
please check from the site
http://rextester.com/MWNVE38245
Store the result into a buffer and when done print the buffer:
#include <stdio.h>
#include <errno.h>
#define RESULT_MAX (42)
size_t get_primes(int * result, size_t result_size, int a, int b)
{
int i, x, f = 1;
size_t result_index = 0;
if (NULL == result) || (0 == result_size) || ((size_t) -1 == result_size))
{
errno = EINVAL;
return (size_t) -1;
}
for (x = a; x <= b; (x++, f = 0))
{
for (i = 2; i < x; i++)
{
if (x % i == 0)
{
f = 1;
break;
}
}
if (f == 0)
{
result[result_index] = x;
++result_index;
if (result_size <= result_index)
{
fprintf(stderr, "Result buffer full. Aborting ...\n");
break;
}
}
}
return result_index;
}
int main(void)
{
int a = 0, b = 0;
int result[RESULT_MAX];
scanf("%d%d", &a, &b);
{
size_t result_index = get_primes(result, RESULT_MAX, a, b);
if ((size_t) -1 == result_index)
{
perror("get_primes() failed");
}
else if (0 == result_index)
{
fprintf(stderr, "No primes found.\n");
}
else
{
printf("%d", result[0]);
for (size_t i = 1; i < result_index; ++i)
{
printf(", %d", result[i]);
}
}
}
return 0;
}
This example uses a simple fixed-size buffer, if this does not suite your needs replace it by a dynamic one.
This is more of a "language-agnostic" problem: "How do I output a comma-separated list without a final comma?" It is not specifically about prime numbers.
You seem to be thinking of you list as a series of [prime comma] units. It isn't. A better way to think of it is as a single prime as the head of the list, followed by a tail of repeated [comma prime] units.
Some pseudocode to illustrate the general idea:
outputList(theList)
separator = ", "
output(theList.firstItem())
while (theList.hasMoreItems())
output(separator)
output(theList.nextItem())
endwhile
return
/* this is just logic */
for(i=2;i<=n;i++)
{
k=0;
for(j=2;j<=i/2;j++)
{
if(i%j==0)
k=1;
}
if(k==0)
{
c++;
c++;
}
}
System.out.println(c);
for(i=2;i<=n;i++)
{
k=0;
for(j=2;j<=i/2;j++)
{
if(i%j==0)
k=1;
}
if(k==0)
{
System.out.print(i);
b++;
if(b!=c-1)
{
System.out.print(",");
b++;
}
}
}
}
}
//comma separated values
#include <bits/stdc++.h>
using namespace std;
int Prime(int a, int n){
bool prime[n+1];
memset(prime,true,sizeof(prime));
for(int p=2;p*p<=n;p++){
if(prime[p]==true){
for(int i=p*p ; i<=n; i+=p ){
prime[i] = false;
}
}
}
for(int i = 2;i<= n;i++){
if(i==2) cout<<i; // here is the logic first print 2 then for other numbers first print the comma then the values
else if(prime[i]) cout<<","<<i;
}
}
int main(){
int a =2 ;
int n = 30;
Prime(a , n);
}
#include <stdio.h>
int main()
{
int i, j, n, count;
scanf("%d", &n);
for(i=2; i<n; i++)
{
count=0;
for(j=2; j<n; j++)
{
if(i%j==0)
count++;
}
if(count==1)
printf("%d," i);
}
printf("\b \b");
}
\b is a nondestructive backspace. It moves the cursor backward, but doesn't erase what's there, it replaces it. For a a destructive backspace,
use "\b \b" i.e. a backspace, a space, and another backspace.
This Program prints all the prime number up to given number with comma separated

Checking if all elements in array are zero

I'm having trouble determining if two words entered are anagrams.
#include <stdio.h>
#include <string.h>
int main() {
char ch;
int letter_count[26] = {0};
int i;
int sum = 0;
printf("Enter first word: ");
do
{
scanf("%c", &ch);
letter_count[ch - 'a']++;
} while (ch != '\n');
for(i = 0; i < 26; i++)
printf("%d ", letter_count[i]);
printf("\n");
printf("Enter second word: ");
do
{
scanf("%c", &ch);
letter_count[ch - 'a']--;
} while (ch != '\n');
for(i = 0; i < 26; i++)
printf("%d ", letter_count[i]);
for(i = 0; i < 26; i++)
if(letter_count[ch] != 0)
sum++;
if (sum == 0)
printf("anagrams");
else
printf("not anagrams");
}
I have to use the do while part of the code. I can enter the two words, and it prints out the elements in the array, so that "Mattress" and "Smartest" together would have all the elements be zero. However, I'm having trouble with the last part, which is to use a third loop to check whether all the elements are zero.
I figured I could declare an int before hand and have it increment whenever an element wasn't zero, and I could just have any sum greater than zero not be an anagram. However, it always prints out anagram for me.
In your third loop, using letter_count[ch] will not check the entire array. You should iterate through the array using the loop variable i. That part of the code should be:
for (i=0; i<26; i++)
if (letter_count[i] != 0)
sum++;
To handle both upper case and lower case letters, use topper() or to lower() in <ctype.h> to avoid out-of-bound access.
#include <stdio.h>
#include <string.h>
#include <ctype.h> // <---
int main() {
char ch;
int letter_count[26] = {0};
int i;
_Bool bad = 0;
printf("Enter first word: ");
do
{
scanf("%c", &ch);
if(!isalpha(ch)) // <---
{
puts("Not a letter");
continue;
}
letter_count[tolower(ch) - 'a']++; // <---
} while (ch != '\n');
for(i = 0; i < 26; i++)
printf("%d ", letter_count[i]);
printf("\n");
printf("Enter second word: ");
do
{
scanf("%c", &ch);
if(!isalpha(ch)) // <---
{
puts("Not a letter");
continue;
}
letter_count[tolower(ch) - 'a']--; // <---
} while (ch != '\n');
for(i = 0; i < 26; i++)
printf("%d ", letter_count[i]);
printf("\n"); // <---
for(i = 0; i < 26; i++)
if(letter_count[i] != 0)
{
bad = 1;
break; // <---
}
if (bad == 0)
printf("anagrams");
else
printf("not anagrams");
}
Take a look at all places marked // <---.

Chess Game with C ,alignment issue

First of all, i don't know if the word alignment is the correct one to describe what i want help for so that's why i provide images from the console application.
I want to know if there is a way to make the zeros be in order . I am providing to you my code .
#include <stdio.h>
#include <stdlib.h>
int emptynes(int table1[16],int table2[16],int zero[32])
{
int i,k=1;
for(i=0;i<16;i++)
{
table1[i]=k;
k++;
}
k=17;
for(i=0;i<16;i++)
{
table2[i]=k;
k++;
}
for(i=0;i<32;i++)
zero[i]=0;
return table1,table2,zero;
}
int firstloop(int table1[16])
{
int i;
for(i=0;i<16;i++)
{
if(i==8)
printf("\n\n");
printf("%d ",table1[i]);
if(i<9)
printf(" ");
else
printf(" ");
}
}
int zeroloop(int zero[16])
{
int i;
for(i=0;i<32;i++)
{
if(i%8==0)
printf("\n\n");
printf("%d ",zero[i]);
}
}
int secondloop(int table2[16])
{
int i;
for(i=0;i<16;i++)
{
if(i==8)
printf("\n\n");
printf("%d ",table2[i]);
if(i<9)
printf("");
}
}
int twomoves(int x,int table1[16],int zero[32])
{
int i,p=0,l=0;
for(i=0;i<16;i++)
{
if(x==table1[i])
{
p=i;
break;
}
}
if(i>8)
l=table1[i]-8;
if(zero[l]==0&&zero[l+8]==0)
{
zero[l+7]=table1[i];
table1[i]=0;
}
return zero,table1;
}
int main()
{
printf("\n\n\n");
int table1[16],table2[16],zero[32];
int i,x,y,p;
emptynes(table1,table2,zero);
firstloop(table1);
zeroloop(zero);
printf("\n\n");
secondloop(table2);
printf("\n\n\n");
printf("Player 1: Pawn & Moves -> ");
scanf("%d %d",&x,&y);
twomoves(x,table1,zero); // do it as loop
firstloop(table1);
zeroloop(zero);
printf("\n\n");
secondloop(table2);
return 0;
}
Use a width specifier:
// Use (at least) 2 chars.
printf("%2d ", table1[i]);
// Use (at least) 2 chars. The minus means left adjustment.
printf("%-2d ", table1[i]);
// Use (at least) 2 chars, zero-padded.
printf("%02d ", table1[i]);
Output:
7
7
07

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