Thread: need some quick help

heya.. I have programming exam tomorrow in C and i've messed up with some notes regrding arrays.. i'm looking for 2 programs basically now .. the first is that how can I display a array in accending order.. for example lets say

Code:

arr[6]={22,10,55,9,32,33}

how do I display this in accending or decending order? all I get from google etc is qsort and bubble sort .. however we are not allowed to use built-in function, i remember last time we did it was something comparision or something.. i totally forgot.. ill be thankful if you can write a program that will do it.. the 2nd thing im looking for is that "a 4 digit number is entered through a keyboard, write a program to reverse it" well i know about the char thing but there's some other logic its like number/100/1000 or something like that.. so if u know about it post it.. thanks .. also i'm confused about array swapping.. like if i have 2 arrays as follows

Code:

arr[]={2,3,4,5}

and
brr[]={3.4.5.6}

how do i swap their values, like brr should go to arr and arr value should be stored in brr.. i remember the TEMP thing but dunno how exactly to do it, ill be thankful if u can help.. its 9:49 pm here and i have exam tomorrow at 12:15 PM .. and i'll sleep in the next hour so plz hurry and thanks in advance

Do you know how to make a loop that counts down instead of up?

for the first question, I guess you just have to do swapping using a nested loop!!
try something out..

lol

Code:

for (i=0; i>=10; i--)

if thats what u meant? anyways, if anyone can write the programs for the things i mentioned plz do.. i really need them to analyse the logic before the exam tomorow

thanks

try that where? lol ..

Code:

arr[]={22,31,10,2,51}

if i want to do this manually i can just do

Code:

arr[0]=2;
arr[1]=10;

nd ........ like tht.. i need a logic for this, please write down the logic and i realy need to sleep.. ill wait for 5 minutes and if someone here comes up with serious help, it will be appritiated otherwise im already ........ed off so plz dont post anything useless

Originally Posted by salmansalman

try that where? lol ..

you wrote this for a loop counting down :

Code:

for (i=0; i>=10; i--)

This will not work. First time through, i=0, test the end condition, i=0 which is not >=10 so exit loop.

The trick is to use a variable in the indexing part when you refer to the array.

int i;

arr[i];

Then you can put it in a loop and just spit out every element that corresponds to the iteration you're in.

To do it backwards, initialize i to the maximum, then count down until it's zero. To to the forward direction, do it like a regular loop, initialize at zero, and count up until it's at the maximum. See the tutorial on loops for more information: http://www.cprogramming.com/tutorial/c/lesson3.html

Feel free to use more than one loop.

lol I seriously dont understand ;\\\\\\\\\\\\\

Code:

void main()
{
int arr[5]={100,22,10,103,44}
int order;

for(i=1; i<=5; i--)
{
printf("%d", order);
}

or what, im totaly confused ;\ just 3 hours left for exam.. i request pleas to paste the complete logic for pasting that array into accending order, ill be thankful

Originally Posted by salmansalman

lol I seriously dont understand ;\\\\\\\\\\\\\

Code:

void main()
{
int arr[5]={100,22,10,103,44}
int order;

for(i=1; i<=5; i--)
{
printf("&#37;d", order);
}

Trace through that for loop.

i=1, 1<=5 so do loop. decrement i, now i=0.
i=0, 0 <=5 so do loop. decrement i, now i=-1.
i=-1, -1 <=5 so do loop. decrement i, now i=-2.

See a pattern? Infinite loop.

well thanks for whatever u did i.e flamming and other crap, none of u actually tried to help or helped.. but anyways, thanks.. now just pray (if possible) for me to pass the exam.. im going now and i will never come back to this board, thanks alot

byee

Instead of Salman Khan if you only knew about Yashwant Kanetkar!

Best of luck for your exams! Why you are so sure about above problems. They may not be asked in exams! Just chill dude!

manav lol haha you were right :P anyway I think I did well in the paper.. here are a few objectives I just want to know if they are correct..

Choose the correct

1)If Var is an integer variable var = 5/2 will return a value
a)2.5
b)3
3)2
d)0

2)Minimum value that an integer constant can have is
a)0
b)-32767
c)32767
d)1.701e+38

3)A C Variable cannot start with
a)An Alphabet
b)A Number
c)A Special symbol except underscore
d)Both b & c

4)C Program is converted to machine language with the help of
a)An Editor
b)An Operating system
c)A Compiler
d)none of the above

5)A Pointer is a special variable which can only store
a)Another pointer
b)Integer values
c)Addresses
d)All of the above

I ticked option "c" in 1 .. option "b" in 2nd .. option "d" in 3rd .. option "c" in 4th and option "c" in 5th..

and now true false

1)Each new C instruction has to b e written on seperate line
2) Blank spaces cannot be inserted within a variable name
3)An Integer constant in C must have atleast one decimal point
4)Output of the instruction 'a' + 10 is 75
5) 3+a=10 is not a valid C statement

I did
1) True
2)True
3)False
4)true
5)True

.. these objections carried 10 marks.. please tell me if all the options i choosed were correct if not pls let me know? thanks.