how does increment & for loops work in c?

[clmlbx]

a=2

printf(++a * a++ * a++ * ++a)

answer is 216

how ??

and how is for loop used ?

 

[anantkhaitan]

printf(++a * a++ * a++ * ++a)

bcoz we start count from right side.. now look
++a -> 3
a++ -> 4
a++ -> 5
++a -> 6
and ultimately 6*6*6*6 gives 216

how is for loop used ?

as per the syntax is

for(initialization;condition;value modification){loop body}

Example:

for(int i=0;i<10;i++)cprintf("%d",i);

 

[clmlbx]

what about this

printf(++a*a++*++a)

ans 45

^^^ you mean to say left to right

why did u took

6*6*6*6

what is the difference between pre & post increment

 

[timemachine]

Pre increment : Increment then operate
Post increment : Operate then increment

 

[Yamaraj]

Guess you people skipped sequence points and their importance while reading your books. And BTW, that code is non-standard.

 

[anantkhaitan]

@clmlbx
You are correct brother..What I told you was my CBSE based bookish knowledge.. I am sorry for that..
It should have been : 4*3*3*3 thats what logic says ..Well today I tried the program (GCC) and output was 108 equals to 4*3*3*3

#include<stdio.h>
int main()
{
int a=2;
printf("%d",++a*a++*a++*++a);
}

For your second problem the answer should be 36 i.e. 4*3*3 and that is what I got after compiling

 

[Pathik]

a=2

printf(++a * a++ * a++ * ++a)

answer is 216

how ??

and how is for loop used ?

See
++a means a is first incremented then used and a++ means a is first used then incremented.
So this would mean (3*3*4*6) = 216

what about this

printf(++a*a++*++a)

ans 45

^^^ you mean to say left to right

why did u took

6*6*6*6

what is the difference between pre & post increment

And this would mean (3*3*5) = 45..
Though the ansewrs may vary with the compiler used.

 

[The_Devil_Himself]

^^exactly guys listen up!!different compiler interprets these increments inside printf statements differently afaik,so its like try before you use kind of thing.

 

[clmlbx]

can it be more clear ?

add one before or after it is the same thing ..............

how will this program work?

1
12
123
1234
12345

I know using "for" loops and using "\t,\n" but how ............

*
**
***
****
*****,


1
2 4
3 6 9
4 8 12
5 10 15 20



*
**
***
****
*****

 

[fun2sh]

its simple. wen priority is same then unirary exp are evaluated from right to left.
so here is wat happens for
1. a++ -----> means the current value of 'a' is used in exp then it is incremented
2. ++a------> means the current value is incremented by 1 first then that new incremented value is used in the code.

so for ur exp
++a..................*...............a++................... *........a++ ....................* ++a
3 (first incre ..................3 (use then ............. 4(use curren ......................6(coz last a=5)
then use,a=3 now)..........incre,a=4 now)..........then incre,a=5now

 

[clmlbx]

guys I know this is not correct but can someone write that programme for me ..
these are like examples, I have many of them ,so if I got to know how u did this then I will try others

post no. 9

 

[QwertyManiac]

Here you go. 3 simple loop constructs. The i-loop is used for the number of lines to print, and the j-loop is used to display the content needed.

#include<stdio.h>

int main(void)
{
	int i,j;
	
	for(i=1;i<6;i++)
	{
		for(j=1;j<i+1;j++)
		{
			printf("%d ",j);
		}
		printf("\n");
	}
	
	printf("\n");
	
	for(i=1;i<6;i++)
	{
		for(j=1;j<i+1;j++)
		{
			printf("* ");
		}
		printf("\n");
	}
	
	printf("\n");
	
	for(i=1;i<6;i++)
	{
		for(j=1;j<i+1;j++)
		{
			printf("%d ",i*j);
		}
		printf("\n");
	}
	
	printf("\n");
	return 0;
}

Outputs as:

1 
1 2 
1 2 3 
1 2 3 4 
1 2 3 4 5 

* 
* * 
* * * 
* * * * 
* * * * * 

1 
2 4 
3 6 9 
4 8 12 16 
5 10 15 20 25

 

[Pathik]

#include<stdio.h>

int main(void)
{
int i,j;

for(i=1;i<6;i++)
{
for(j=1;j<i+1;j++)
{
printf("*");
}
printf("\n");
}

printf("\n");
return 0;
}
Arey just remove the SPACE after the * in the printf.

 

[clmlbx]

hi

this all are from left

how can I give output from right ?

means output to right side of screen

 

[Pathik]

Do u need output starting from the right side of the screen or aligned to the right??

 

[clmlbx]

STARTING FROM THE RIGHT SIDE AND ALSO ALIGNED TO RIGHT

AGAIN CAPS.......*gigasmilies.googlepages.com/actions1.gif

 

[Faun]

STARTING FROM THE RIGHT SIDE AND ALSO ALIGNED TO RIGHT

AGAIN CAPS.......*gigasmilies.googlepages.com/actions1.gif

Use ur intuition to solve this

I know u can do it*farm3.static.flickr.com/2074/2106526281_d24c2bda14_o.png, ,and stop forgetting,probably u will suffer from Alzhemeir later. Make ur barin sharp*farm3.static.flickr.com/2398/2107306002_6240bfbc60_o.png

 

[aditya_v]

guys, what solutions u are giving is wrt TC only
C++ doesn't enforce this issue, as said by Bjarne Stroustrup

What's the value of i++ + i++?

It's undefined. Basically, in C and C++, if you read a variable twice in an expression where you also write it, the result is undefined. Don't do that. Another example is:

v = i++;

Related example:

f(v,i++);

Here, the result is undefined because the order of evaluation of function arguments are undefined.

Having the order of evaluation undefined is claimed to yield better performing code. Compilers could warn about such examples, which are typically subtle bugs (or potential subtle bugs). I'm disappointed that after decades, most compilers still don't warn, leaving that job to specialized, separate, and underused tools.

 

[QwertyManiac]

hi

this all are from left

how can I give output from right ?

means output to right side of screen

Look for Output flags (printf flags) in your text book. Do the guys at Ape-tech not teach you ANYTHING at all? These questions are very trivial even for a new programmer!

 

[clmlbx]

Look for Output flags (printf flags) in your text book. Do the guys at Ape-tech not teach you ANYTHING at all? These questions are very trivial even for a new programmer!

I missed one class and then to I want to complete this assignment to make a good impression .( my prevoious was not good )


nothing more, and here guys are to help so I asked.....