Saturday, November 7, 2015

Funny C Program:Comparison Between Zhishen Lu Eating Steamed Bun v5 and v6

Acturally,I mentioned the difference between the 5th version and 6th one in Funny C Program:Zhishen Lu Eating Steamed Bun v6,so I am not going to repeat it.Let's discuss whether to assign values to every array element one by one through a loop statement or not.To find the reasonable explanation,I tested a few programs on C4droid.

//Testing program 1
#include <stdio.h>
int main(void)
{
int i,array[101]={0};
for(i=1;i<101;i++)
printf(" %d",array[i]);
return 0;
}

Following is the result.


Testing program 1


What?It depends on the scale of the array?
I was puzzled,and modified the code like testing program 2.

//Testing program 2
#include <stdio.h>
int main(void)
{
int i,array[3]={0};
for(i=0;i<3;i++)
printf(" %d",array[i]);
printf("\n");
return 0;
}

The result is following.


Testing program 2

It seemed that scale of the array did influence the result.To convince myself,testing program 3 came into being.Of course there were many other testing programs which I'm unable to show to you one after another.

//Testing program 3
#include <stdio.h>
int main(void)
{
int i,array[6]={0};
for(i=0;i<6;i++)
printf(" %d",array[i]);
printf("\n");
return 0;

}

And the result is following.


Testing program 3


As expected,not all the elements equal 0.
How can we explain it?Maybe it's because different compilers deal with "int a[10]={0};" variously,I think.To avoid mistakes,why not write a loop statement?I'm sorry that I didn't want to write another circle statement,so the mistake appeared.But I feel lucky for learning so much from it.
Of course,if you understand the exact explanation of this mistake,welcome to post a comment or email me at jimzhou001@gmail.com.Thank you!

Friday, November 6, 2015

Funny C Program:Zhishen Lu Eating Steamed Bun v6

Because of my puzzle,I'd like to share the modified code straightly,hoping you can explain why to alter like this.

//Zhishen Lu Eating Steamed Bun v6
#include <stdio.h>
int main(void)
{
int monk[101],count=0,steabun=0,i;//Easy to count.monk[1]~monk[100] for the flower monk Zhishen Lu and other 99 monks,count to number off,steabun for the number of steamed buns already divided and i as a simple counter.
for (i=1;i<101;i++)
monk[i]=0;//Initialization of the array.Value 0 means they will participate in numbering off.
i=0;
while (steabun<99)
{
if (++i<=100&&!monk[i])//Make sure that the monk hasn't got a steamed bun yet
{
if (++count%5==0)
{
monk[i]=1;//Get a steamed bun
steabun++;
}
}
else if (i>100)
i=0;//Make sure to mumber off continuously
}
for(i=1;monk[i];i++) ;//Do you know why ";" exists?
printf("The position number of Zhishen Lu is %d.\n",i);
return 0;
}

Find any differences between the 6th version and the 5th one?
Right,we initialised monk[1] to monk[100] through a "for" circle in the latest version while not when defining the array.
But I learned from the textbook that an array could be defined and initialized like this:"int a[10]={0};"which means every array element equals 0.Then what's wrong with the 5th version?If interested,pay attention to my posts.

Funny C Program:Zhishen Lu Eating Steamed Bun v5

"If the two conditions of judgement mentioned in the previous version are combined together,will the problem be solved?"I asked myself.Then I tried to make it again and again.
The process was tough.You might notice that in the previous version,expressions in brackets are both in contrast to the right conditions to continuously number off.As I tried to put them together,using "&&" or "||" was a thorny problem.I tried many times,but still in vain.Eventually,I noticed that the right condition is very certain.Why not number off directly as the expression meets the condition?As to other cases,consider them expectly.
Here comes the 5th version of this program.

//Zhishen Lu Eating Steamed Bun v5
#include <stdio.h>
int main(void)
{
int monk[101]={0},count=0,steabun=0,i=0;//Easy to count.monk[1]~monk[100] for the flower monk Zhishen Lu and other 99 monks,value 0 means they will participate in numbering off.count to number off,steabun for the number of steamed buns already divided and i as a simple counter.
while (steabun<99)
{
if (++i<=100&&!monk[i])//Make sure that the monk hasn't got a steamed bun yet
{
if (++count%5==0)
{
monk[i]=1;//Get a steamed bun
steabun++;
}
}
else if (i>100)
i=0;//Make sure to mumber off continuously
}
for(i=1;monk[i];i++) ;//Do you know why ";" exists?
printf("The position number of Zhishen Lu is %d.\n",i);
return 0;
}

How about this version?Seems perfect?No!
The screen showed nothing at all when running this program.
But I couldn't discover the errors by myself.I looked for help from a friend,and the problem was solved successfully.But it's not convictive enough,I thought.Want to know more about the next version?It's coming soon!

Wednesday, November 4, 2015

Funny C Program:Zhishen Lu Eating Steamed Bun v4

Maybe you have already been impatient,or you got the right answer through your own efforts.However,the steps of my sharing will not stop.
Since if-else statement can't prevent "while" circle increasing i to101,why not swap their places?Putting the if-else statement behind the "while" circle could effectively avoid i becoming greater than 100.
Following is the source code.

//Zhishen Lu Eating Steamed Bun v4
#include <stdio.h>
int main(void)
{
int monk[101]={0},count=0,steabun=0,i=0;//Easy to count.monk[1]~monk[100] for the flower monk Zhishen Lu and other 99 monks,value 0 means they will participate in numbering off.count to number off,steabun for the number of steamed buns already divided and i as a simple counter.
while (steabun<99)
{
while (monk[i])
i++;//Make sure that the monk hasn't got a steamed bun yet
if (i<100)
i++;
else
i=1;//Make sure to mumber off continuously
if (++count%5==0)
{
monk[i]=1;//Get a steamed bun
steabun++;
}
}
for(i=1;monk[i];i++) ;//Do you know why ";" exists?
printf("The position number of Zhishen Lu is %d.\n",i);
return 0;
}

Facts showed that I was in vain.You may have run the program,so what sentence was on the screen?"The position number of Zhishen Lu is 1."It looked like that I returned to the origin.
Acturally,after every circle,i is reset to 1 and the elder,who is the first monk,will participate in numbering off regardless of the value of monk[1].In the meantime,if monk[100] equals 1,"while" circle will add 1 to i,which means the compiler is going to determine whether the value of monk[101] equals 0 or not.That's what we don't expect.