C Programming - C Preprocessor - Discussion
Discussion Forum : C Preprocessor - Find Output of Program (Q.No. 8)
8.
What will be the output of the program?
#include<stdio.h>
#define FUN(i, j) i##j
int main()
{
int va1=10;
int va12=20;
printf("%d\n", FUN(va1, 2));
return 0;
}
Answer: Option
Explanation:
The following program will make you understand about ## (macro concatenation) operator clearly.
#include<stdio.h>
#define FUN(i, j) i##j
int main()
{
int First = 10;
int Second = 20;
char FirstSecond[] = "IndiaBIX";
printf("%s\n", FUN(First, Second) );
return 0;
}
Output:
-------
IndiaBIX
The preprocessor will replace FUN(First, Second) as FirstSecond.
Therefore, the printf("%s\n", FUN(First, Second) ); statement will become as printf("%s\n", FirstSecond );
Hence it prints IndiaBIX as output.
Like the same, the line printf("%d\n", FUN(va1, 2)); given in the above question will become as printf("%d\n", va12 );.
Therefore, it prints 20 as output.
Discussion:
7 comments Page 1 of 1.
Sravanireddy said:
1 decade ago
Hey first second concatenation is first second.
In the same way 10 and 2 should be 102.
Any one please explain.
In the same way 10 and 2 should be 102.
Any one please explain.
(1)
Naveen Kumar Chaudhary said:
1 decade ago
## is the token concatenation or token pasting operator.
You can even use it to form longer numbers like 1.5##e3 will give you 1.5x10^3 or it can be used for string concatenation.
Here val##2 -->val2.
You can even use it to form longer numbers like 1.5##e3 will give you 1.5x10^3 or it can be used for string concatenation.
Here val##2 -->val2.
(1)
Akash said:
1 decade ago
Great job indiabix!!!
Ravitheja said:
1 decade ago
@sravani. here val1##2 ==val12
Pradeep Kumar said:
1 decade ago
#include<stdio.h>
#define FUN(i, j) i##j
int main()
{
int va1=10;
int va12=20;
printf("%d\n", FUN(va1, 2));
return 0;
}
Here ## is the token concatenation operator.
FUN(val,2)is
val##2 its give val2
So printf("%d\n",val2) give 20.
#define FUN(i, j) i##j
int main()
{
int va1=10;
int va12=20;
printf("%d\n", FUN(va1, 2));
return 0;
}
Here ## is the token concatenation operator.
FUN(val,2)is
val##2 its give val2
So printf("%d\n",val2) give 20.
A.S Bhullar said:
1 decade ago
Isn't it error, is va1va12 is valid identifier in this program?
Atiq said:
8 years ago
You are right @Pradeep Kumar.
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