C Questions and Answers – Conditional Preprocessor Directives – 1

This set of C Multiple Choice Questions & Answers (MCQs) focuses on “Conditional Preprocessor Directives – 1”.

Pre-requisite for this C MCQ set: Advanced C Programming Video Tutorial.

1. What will be the output of the following C code?

#include<stdio.h>
#define max 100
main()
{
    #ifdef max
    printf("hello");
}

a) 100
b) hello
c) “hello”
d) error
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2. _______________ is the preprocessor directive which is used to end the scope of #ifdef.
a) #elif
b) #ifndef
c) #endif
d) #if
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3. What will be the output of the following C code?

#include<stdio.h>
void main()
{
    #ifndef max
    printf("hello");
    #endif
    printf("hi");
}

a) hello
b) hellohi
c) error
d) hi
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4. What will be the output of the following C code?

#include<stdio.h>
#define san 557
int main()
{
    #ifndef san
    printf("yes");
    #endif
    printf("no");
}

a) error
b) yes
c) no
d) yesno
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5. The preprocessor directive which checks whether a constant expression results in a zero or non-zero value __________
a) #if
b) #ifdef
c) #undef
d) #ifndef
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6. What will be the output of the following C code?

#include<stdio.h>
#define max 100
void main()
{
    #if(max%10)
    printf("san");
    #endif
    printf("foundry");
}

a) error
b) san
c) foundry
d) sanfoundry
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7. The preprocessor directive which is used to remove the definition of an identifier which was previously defined with #define?
a) #ifdef
b) #undef
c) #ifndef
d) #def
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8. What will be the output of the following C code?

#include<stdio.h>
#define hello 10
void main()
{
    printf("%d",hello);
    #undef hello
    printf("%d",hello);
}

a) 10
b) hello
c) error
d) 1010
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9. What will be the output of the following C code?

#include <stdio.h>
#define a 2
main()
{
    int r;
    #define a 5
    r=a*2;
    printf("%d",r);
}

a) 10
b) 4
c) 2
d) 5
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10. What will be the output of the following C code if the value of ‘p’ is 10 and that of ‘q’ is 15?

#include<stdio.h>
int main()
{
    int p,q;
    printf("Enter two numbers\n");
    scanf("%d",&p);
    scanf("%d",&q);
    #if(4<2)
    printf("%d",p);
    #elif(2>-1)
    printf("%d",q);
    #else
    printf("bye");
    #endif
}

a) 10
b) 15
c) bye
d) error
View Answer

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