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the output numbers are wrong why ?
the program is used to get factorial of a number using recursion
and if you know sites to practice more examples I will be thankful for you
#include <stdio.h>
#include <stdlib.h>
int factorial(int a);
int main()
{
int n,x;
printf("enter ur number ");
scanf("%d",&x);
n=factorial(x);
printf("the factorial = %d",n);
return 0;
}
int factorial(int a)
{
int fac;
if(a<=1)
{
if (a<1)
{
fac=0;
}
return fac;
}
printf("the number = %d\n",a);
printf("the factorial = %d\n",fac);
fac = a * factorial(a-1);
This will always return 0, because the last fac will always be 0 and it multiplies all the other results. Change that to
if(a<1)
fac=1;
Also indent your code properly.
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So I got this question in my end-sem:
//The value returned by sam(3,0) of the below function is:
#include <stdio.h>
int sam(int n,int a)
{
if(n==0)
return a;
else
{
a+=n;
sam(--n, a);
a+=n;
}
}
I calculate using Tree-method and got the answer as 6. But if I compile and directly print return I get 2.
int main()
{
printf("%ld",sam(3,0));
return 0;
}
OUTPUT: 2
I checked again and again with what is wrong and couldn't understand. The mystery is if I print(a) just before it returns. It returns 6 (what I calculated).
#include <stdio.h>
int sam(int n,int a)
{
if(n==0){
printf("%d",a); //Check the change here
return a;
}
else{
a+=n;
sam(--n,a);
a+=n;
}
}
int main()
{
sam(3,0);
return 0;
}
OUTPUT: 6
If I explain this I get 4 marks. Enough to change my grade
With a bit of formatting assistance, please note that the below function only explicitly returns when n is 0. Otherwise it performs recursion, but uselessly since it never returns any value created by the recursion.
As a result, you find yourself in the realm of undefined behavior.
#include <stdio.h>
int sam(int n, int a) {
if (n == 0)
return a;
else {
a += n;
sam(--n, a);
a += n;
}
}
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#include<stdio.h>
int main(){
int num,i,sum=0;
printf("Enter the number:");
scanf("%d",&num);
for(i=1; i<=10; i++)
{
num = num*i;
sum += num;
}
printf("%d",sum);
return 0;
}
this is the code i have written and i don't know why this is not working?
you should not change the num which is 8 in your case.
do it like this:
#include<stdio.h>
int main(){
int num,i,sum=0;
printf("Enter the number:");
scanf("%d",&num);
for(i=1; i<=10; i++)
{
sum += num*i;
}
printf("%d",sum);
return 0;
}
You’re changing num each time through the loop, so you’re not actually adding the multiples of the input you think you are. Add some logging or run it in a debugger for good visibility into the problem.
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Now im having problems with the new code in terms of compiling. I have two great answers but chux's answer is addressed to rectify my code . So by his/her directions my new code is:
#include <math.h>
#include <conio.h>
int main()
{
int n,i,r;
printf("Enter A Number to know its prime or non prime");
scanf("%d",&n);
for(i=2;i<=n-1;i++)
{
if(n%i==0)
{r==1;
break;
}
}
if(r==1)
printf("%d is a non-prime number",n);
else
printf("%d is a prime number",n);
return 0;
}
But on the output it show as 87 is a prime number. I don't know why. But can someone spot my mistake?
At few problems
Assignment vs. compare
if (r=1) assigns 1 to r, so if (r=1) is always true. Certainly a compare was needed, #Ry
// if (r=1)
if (r == 1)
No early break
OP's code: The value of r depends on the last iteration. Certainly once a factor is found, loop should exit.
for(i=2;i<=n-1;i++) {
if(n%i==0)
// r=1;
{ r = 1; break; }
else
r=0;
}
Incorrect functionality for n == 0,1
All values n < 2 incorrectly report as prime.
Inefficient
Code performs up to n loops. Only need to perform sqrt(n) loops. Tip: Do not use floating point math here for an integer problem.
// for(i=2;i<=n-1;i++)
for(i = 2; i <= n/i; i++)
Alternate
Only peek if you must code.
First off, " ... conio.h is a C header file used mostly by MS-DOS compilers to provide console input/output. It is not part of the C standard library or ISO C .." I was able to get the code to compile without that library file, so you may wish to consider removing it. As for as the code goes, well here is what I came up with:
#include <math.h>
#include <stdio.h>
int isPrime(int value) {
int i = 2;
for(; i < value; i++) {
if((value % i) == 0) {
return 0;
}
}
return value > 1;
}
int main(void){
int n=0,i=0, r=0;
char * s;
printf("\nPlase enter a number to learn if it is prime:");
scanf("%d",&n);
r = isPrime(n);
printf("\n%d is ", n);
s = (r==0)? " not a prime number" : "a prime number";
puts(s);
return 0;
}
After the user inputs a number, the code checks whether it is prime by calling the function isPrime(), a function that returns an int. isPrime is a simple function that attempts to factor a number.
See here for similar live code that I devised.
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I just want to know what is the wrong with it, and how to fix it.
It looks like every thing is right, but when you run the .exe it crash every time
#include <stdio.h>
#include <stdlib.h>
// first list filling function:
void T_filling(int T[],int n){
int i;
for(i=1 ;i<=n ;i++){
printf("enter the number:",i+1);
scanf("%d",&T[i]);
}
}
//then the main algorithm:
int main()
{
int j,k,l;
int n,x;
// you can order up to 100 integer number
int T[100];
printf("This program is to order numbers decreasingly\n");
printf("how many numbers you want to order?\n");
// scanning the number of elements in the list
scanf(n);
//filling the list
T_filling(T[100],n);
//bubble sort Algorithm
for(j=1;j<=n-1;j++){
for(k=1;k<=n-j;k++){
if(T[k+1]>T[k]){
x=T[k];
T[k]=T[k+1];
T[k+1]=x;
}
}
}
for(l=1;l<=n;l++){
//printing the result on screen
printf("%d;",T[l]);
}
printf("\n");
system("pause");
return 0;
}
You are not using scanf and passing the array to function properly.
Please modify these lines in your code as follows and your program will work as expected.
scanf("%d", &n);
//filling the list
while(n > 100)
{
printf("Exceeding size, please re enter the size");
scanf("%d", &n);
}
T_filling(T,n);
Hope this helps.
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I am not finding the correct output of this program.It giving run time error.
#include <stdio.h>
int main()
{
int c = 5, no = 10;
do {
no /= c;
} while(c--);
printf ("%d\n", no);
return 0;
}
It's division by zero. Since you are using a post-decrement in your loop counter c, it is becoming 0 in the last iteration.
Now that you know the reason for the run time error from the answer by #EugeneSh, here's how you can fix it.
do {
no /= c;
} while(--c); // Use pre-increment instead of post-increment.
In addition the all these answer above I just want to say it's better to check whether a number is zero before division -
#include <stdio.h>
int main()
{
int c = 5, no = 10;
do {
if(c!=0){
no /= c;
}
} while(c--);
printf ("%d\n", no);
return 0;
}
This will prevent these kind of runtime error.
Hope it will helps.
Thanks a lot.