C Programming - Pointers - Discussion

Discussion Forum : Pointers - True / False Questions (Q.No. 3)
3.
The following program reports an error on compilation.
#include<stdio.h>
int main()
{
    float i=10, *j;
    void *k;
    k=&i;
    j=k;
    printf("%f\n", *j);
    return 0;
}
True
False
Answer: Option
Explanation:
This program will NOT report any error. (Tested in Turbo C under DOS and GCC under Linux)

The output: 10.000000
Discussion:
23 comments Page 1 of 3.

KRISH BHANDERI said:   2 years ago
@All.

Here is my code;

#include<stdio.h>
int main()
{
float i=10, *j;
void *k;
k=&i;
j=k;
printf("%f\n", *j);
return 0;
}

in the Above program, void pointer holds the Address of Float i

Remember Whenever we use a void pointer we have to typecast it to print the value
printf("%d",*(float*)k);

But here what we done is we assigned the address of i which is hold by k
j=k

now j holds the address of i
So, it will print 10.000000.

Suman said:   10 years ago
This program gives error.

Error 1: error C2440: '=' : cannot convert from 'void *' to 'float *'.

2 IntelliSense: A value of type "void *" cannot be assigned to an entity of type "float *".

Kunal Bansal said:   1 decade ago
I have personally run this program on DEV C++ 4.9.9.2 and it was giving error in line j=k; statement
After type casting it , it is giving the value 10.000000
So this is compiler dependent

Anjaneyareddy said:   1 decade ago
Everything is ok. But 1 thing I can't understood. After printing float value 10.000000. Why printed 6 0's?

Rashmi said:   5 years ago
Before assigning a void pointer => void *k, typecasting has to be done => (int*)k or *((int*)k).

Tripti said:   1 decade ago
It produce an error b/c j does not define as a double pointer and we send in it an address of address.

Kunal Bansal said:   1 decade ago
@kranthi this is an valid prototype
error is because of different thing , read my previous comment

Mohammad said:   8 years ago
In code blocks on windows 7.

Error: invalid conversion from 'void*' to 'float*' [-fpermissive].

Kranthi said:   1 decade ago
No, Its an error. How come you declare a variable with Void prototype. Void means nothing.

Rahul said:   1 decade ago
The above code is correct. It gave no error during compilation or during running in gcc.


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