What's the output of this C program?

VIJAYSY · 2014-04-27T18:19:07+00:00

[HASHTAG]#include[/HASHTAG]<stdio.h> int main(){ int i=2,j=2; while(i+1?--i:j++) printf("%d",i); return 0; } The above question was asked for my seniors in Mu-Sigma written test.. The output for the above code is 1. I don't know how it is 1 , help me to to understand.

What's the output of this C program?

VIJAYSY
@vijaysy-L0Tg5s

Updated: Oct 26, 2024

Views: 1.3K

[HASHTAG]#include[/HASHTAG]<stdio.h>
int main(){
int i=2,j=2;
while(i+1?--i:j++)
printf("%d",i);
return 0;
}

The above question was asked for my seniors in Mu-Sigma written test..
The output for the above code is 1. I don't know how it is 1 , help me to
to understand.

0

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smorgasbord

Member • Apr 27, 2014

#include<stdio.h> // Includes the standard library.

int main(){       // Main function
int i=2,j=2;      // Sets 2 variables ( i and j ) to values of 2.
while(i+1?--i:j++)  // Loops while i+1 is true ( not zero ), and decreases i and increases j
printf("%d",i);     // Shows the output of i at every iteration of the loop
return 0;           // end of the main function, returns 0.
}

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Mansi Munjal

Member • Oct 26, 2014

hey...can anyone help me to understand the logic of star patterns program??pls help...

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Neeraj Kumar Singh

Member • Oct 26, 2014

Mansi Munjal
hey...can anyone help me to understand the logic of star patterns program??pls help...
It works like 2 D array.

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Mansi Munjal

Member • Oct 26, 2014

Neeraj Kumar Singh
It works like 2 D array.
Actually i am confused in first loop which is for row.Sometime it initialized from 1 and sometime frim 5.pls xplain

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Neeraj Kumar Singh

Member • Oct 26, 2014

Mansi Munjal
Actually i am confused in first loop which is for row.Sometime it initialized from 1 and sometime frim 5.pls xplain
first loop is for no of rows.
it doesnt matter whether it z strt from 0 or 5.
if we strt from 0
den the for loop like thz for(int i=0;i<5;i++)
if we strt from 5
den the for loop like for(int i=5;i>0;i--)

in both d cases no of rows remains same i.e 5.

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Neeraj Kumar Singh

Member • Oct 26, 2014

Mansi Munjal
Actually i am confused in first loop which is for row.Sometime it initialized from 1 and sometime frim 5.pls xplain
sometime first for loop depends upon pattern.

foe eg.
pattern like thz
5 5 5 5 5
4 4 4 4
3 3 3
2 2
1

code:
#include<iostream.h>
#include<conio.h>
int main()
{
clrscr();
for(int i=5;i>=1;i--)
{
for(int j=1;j<=i;j++)
{
cout<<i<<" ";
}
cout<<endl;
}
getch();
}

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Mansi Munjal

Member • Oct 26, 2014

thank you so much....but can you explain me more clearly that how can i get to know from where i will start the loop.

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Mansi Munjal

Member • Oct 26, 2014

#include<stdio.h>
void main()
{
int i,j;
for(i=1;i<=5;i++)
{
for(j=1;j<=i;j++)
{
printf("*");
}
printf("\n");
}
}

output
*
**
***
****
*****
i understand this program cz loop is start from 1.
but in

#include<stdio.h>
void main()
{
int i,j,k;
for(i=5;i>=1;i--)
{
for(j=1;j<i;j++)
{
printf(" ");
}
for(k=5;k>=i;k--)
{
printf("*");
}
printf("\n");
}
}

output
*
**
***
****
*****
but why in this loop i and k started from 5??????

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Saandeep Sreerambatla

Member • Oct 27, 2014

VIJAYSY
[HASHTAG]#include[/HASHTAG]<stdio.h>
int main(){
int i=2,j=2;
while(i+1?--i:j++)
printf("%d",i);
return 0;
}

The above question was asked for my seniors in Mu-Sigma written test..
The output for the above code is 1. I don't know how it is 1 , help me to
to understand.
You have to understand one thing here,

there are no brackets after while loop so it executes only once.

so what does the statement say?

while(i+1"--i:j++)

so value of i is 2, so while(3) -- this is true. so --i will return you 1 and that is printed.

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Neeraj Kumar Singh

Member • Oct 27, 2014
Mansi Munjal
```
#include<stdio.h>
void main()
{
int i,j;
for(i=1;i<=5;i++)
{
for(j=1;j<=i;j++)
{
printf("*");
}
printf("\n");
}
}
```
output
*
**
***
****
*****
i understand this program cz loop is start from 1.
but in
```
#include<stdio.h>
void main()
{
int i,j,k;
for(i=5;i>=1;i--)
{
for(j=1;j<i;j++)
{
printf(" ");
}
for(k=5;k>=i;k--)
{
printf("*");
}
printf("\n");
}
} 
```
output
*
**
***
****
*****
but why in this loop i and k started from 5??????
output for above program is thz..
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Neeraj Kumar Singh

Member • Oct 27, 2014
Mansi Munjal
```
#include<stdio.h>
void main()
{
int i,j;
for(i=1;i<=5;i++)
{
for(j=1;j<=i;j++)
{
printf("*");
}
printf("\n");
}
}
```
output
*
**
***
****
*****
i understand this program cz loop is start from 1.
but in
```
#include<stdio.h>
void main()
{
int i,j,k;
for(i=5;i>=1;i--)
{
for(j=1;j<i;j++)
{
printf(" ");
}
for(k=5;k>=i;k--)
{
printf("*");
}
printf("\n");
}
} 
```
output
*
**
***
****
*****
but why in this loop i and k started from 5??????
[HASHTAG]#include[/HASHTAG]<stdio.h>
void main()
{
int i,j,k;
for(i=5;i>=1;i--)
{
for(j=1;j<i;j++) // if i=5 den 4 spaces
{
printf(" ");
}
for(k=5;k>=i;k--) /*if i=5 thz loop runs only one time so,its print 1 star,if i=4 den runs two times 2 star bcz k =5 and i=4 5>=4 (true) ,k-- k=4 ,i=4,4>=4 (true) and den k-- k=3 ,i=4 3>=4 (false) it comes out of the loop.*/

{
printf("*");
}
printf("\n");
}
}
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Neeraj Kumar Singh

Member • Oct 27, 2014
Mansi Munjal
```
#include<stdio.h>
void main()
{
int i,j;
for(i=1;i<=5;i++)
{
for(j=1;j<=i;j++)
{
printf("*");
}
printf("\n");
}
}
```
output
*
**
***
****
*****
i understand this program cz loop is start from 1.
but in
```
#include<stdio.h>
void main()
{
int i,j,k;
for(i=5;i>=1;i--)
{
for(j=1;j<i;j++)
{
printf(" ");
}
for(k=5;k>=i;k--)
{
printf("*");
}
printf("\n");
}
} 
```
output
*
**
***
****
*****
but why in this loop i and k started from 5??????
we can write thz code also like thz
[HASHTAG]#include[/HASHTAG]<stdio.h>
void main()
{
int i,j,k;
for(i=1;i<=5;i++)
{
for(j=4;j>=i;j--)
{
printf(" ");
}
for(k=1;k<=i;k++)
{
printf("*");
}
printf("\n");
}
}

basically its all depend upon ur logic .
always dry run ur code on paper.
it is the best way to understand the any program. 😀
Happy coding.. 😀
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RajeevKumarsingh

Member • Oct 28, 2014

Saandeep Sreerambatla
You have to understand one thing here,

there are no brackets after while loop so it executes only once.

so what does the statement say?

while(i+1"--i:j++)

so value of i is 2, so while(3) -- this is true. so --i will return you 1 and that is printed.
Hey Sandeep you are right.
Since i+1 will always be true so first value is going to execute that is --i. This make the value of i to be 1.
Next is while loop, with null statement nothing will happen. The value of i remain 1 which get printed as output.

At the same contrary to this question. Execute the following and tell the output and the reason.
[HASHTAG]#include[/HASHTAG]<stdio.h>
int main(){
int i=2,j=2;
while(i+1?--i:j++){
j=0;
}
printf("%d",i);
return 0;
}

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Gaurav Zagade

Member • Oct 28, 2014

There is no 1D or 2D array taken i mean to say doesn't taken any array..In while the conditional operator(?) is used if you dont know the concept of conditional operator then you will never understand the program. before entering into the program while i+1 if this condition is treated as true then it will goes to --i which is predecrementation now you will ask me how this i+1 will treated as true,In conditional operator or any if else statement non zero value is treated as true So in first loop i+1 value becomes 3 which is non zero value so it will treated as true and execute --i statement which is predecrementation,now the value of i was 2 after the predecrementation it will becomes 1,Therefore it will print 1.if you write i--(Postdecrementation)in that while condition then 1st it will print 1 then after it will print 0,because in Postdecrementation the old value(which is 1) is first assign and then it will decremented that means
2-1=1//old value
1-1=0
the output will print 1 and 0
now here 0 is treated as false so loop will stop here.

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Mansi Munjal

Member • Oct 28, 2014

Neeraj Kumar Singh
we can write thz code also like thz
[HASHTAG]#include[/HASHTAG]<stdio.h>
void main()
{
int i,j,k;
for(i=1;i<=5;i++)
{
for(j=4;j>=i;j--)
{
printf(" ");
}
for(k=1;k<=i;k++)
{
printf("*");
}
printf("\n");
}
}

basically its all depend upon ur logic .
always dry run ur code on paper.
it is the best way to understand the any program. 😀
Happy coding.. 😀
thankuu so much...seriously thanks..

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Neeraj Kumar Singh

Member • Oct 28, 2014

Mansi Munjal
thankuu so much...seriously thanks..
U r Most welcome #-Link-Snipped-# .... 😀

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