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+36 votes

Consider the following C program.

int main() {
    char* c=”GATECSIT2017”;
    char* p=c;
    printf(“%d”, (int)strlen(c+2[p]-6[p]-1));
    return 0;

The output of the program is _______

in Programming by Active (1.6k points)
edited by | 8.6k views
In que. it was asked about strlen that would be 2
what was actual que . does this contain both printf line .......
Actual one had strlen wala .
i will just explain this wait for 5 min .....
"(int)" is it use for type casting???
Acc to me, the value at address 110 is 1 not 7 ,how you have taken 7 which is at 111

now solve again 


9 Answers

+60 votes
Best answer
char c[]="GATECSIT2017";
char *p=c;

$2[p] = *(2+p) = p[2]$
$6[p] = *(6+p) = p[6]$
$c + 2[p] - 6[p] -1 = c + 'T' - 'I' - 1 = c + 11 - 1 = c + 10$ (In any character coding all alphabet letters are assigned consecutive int values as per C)

printf will print $2$ which is the length of "$17$".

by Veteran (425k points)
edited by

sir i believe the question was a numerical answer type and had only one output which was to print just 2,

i remember that there was only one

printf statement which was


kindly change the question as it can be misleading

leave it for now. When the answer response comes, all the questions will be renetered. It should be coming next week.
why it is tycasted?
How do i 17 lenth ans is 2 Pls Explain ?
strangely counting position of alphabet number worked out here c is c[0]=g (7th position in alphabet) , similarly T=20th , I is 11th (7+20-11-1) :D , do you think it will work for every case ?
Strlen returns unsigned values ... thats y type cast is needed ...

@ Puja Mishra 

If we type cast and value of strlen is negative then what happens ?

ex : strlen(-2); // output 2

(int)strlen(-2); // what is the output ?

In the strlen why we are not considering null as last character? It means I want to say that strlen should return length as 3. Please correct me if I am wrong
in strlen implementation while loop works till not equal to '\0'. So strlen will return the length of string excluded with null character hence in this case length will be 2.
Nice explanation
i didnt understand, anyone please explain how 11 and 1 value corresponds to T & I ?
+28 votes

I hope now you can understood easily

by Active (3.9k points)
how you start "c" address from 100. what need to do "110 %5"??? kindly plz explain...
you can assume any starting address for array . ANswer would be same .
%s=17 please explain
%s=17 here bcz of

Since address is now 110. So from 110 it will print whole string i.e 17

can we index arrays like 2[p] ???

Any reference.
How u took size of char as 1?? I mean they didn't mentioned 1 or 2 bytes??
+20 votes

Hope it might help.......

by Boss (41.9k points)
1010 means from 10 th position consider complete string?
+8 votes
The answer wil be 2.
This was asked , c+2[p]-6[p]-1
Look at 2[c] - 6[p] this will be evaluate as ( T -  I)

the difference in ascii walue of T and I will be 11.
So it will boil down to c + 11-1

means c+10  and the address for stringlength will become like strlength("17');

That is 2
by Boss (16k points)
how c+10 become "17"?? kindly eplain

(ascii value of c) + 10 (make sure ascii value of 'c' is relative to the value choosen in 't' and 'i' in previous steps )
Ascii value of C is not used here, C is the starting address of the array and C+10 is the address of the 11th element of the Array, now strlen starts counting from the address passed to it as argument and stops when it finds '\0'(null- by default added at the end of any array of characters- string) but while counting array length strlen does not add extra 1 for this null character, so starting  from C+10, strlen finds that C+12 is null('\0), hence stops and returns length as 2
in ASCII table all alphabets are listed in consecutive locations, so you can assume  a is  1 , then b is 2 , c is 3 , d is 4, e is 5, f is 6, g is 7 on till z=26,

now given in question C +10, where C gives the value of starting address of the array , i,e value of G which is 7

so C+7 turns out to be 17 , i hope this helps

@Sourav Basu @Arjun  @Shaik Masthan (sorry for disturbing you )

sir the result is c+10 which (on considering c = 1000) gives 1010.

then shouldn't it be strlen(1010)   why are we taking element at that address as dereferencing operator is not used *(c+10) would give "17"  ...pls tell me where i am getting wrong.



read first concept of strlen function before attempting the question


same doubt please let know if u get it.

+2 votes

Hope this helps!

by Junior (815 points)
0 votes

output is 2

by (101 points)
0 votes

answer is 2

by (269 points)
0 votes

2 is the answer.

by Boss (35.7k points)

@MiNiPanda @Shaik Masthan

when pointer subtraction is directly allowed then why here we are subtracting ASCII value why not address?


2[p] or 6[p] are not pointers, those are elements

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