Questions and answers for exam Preparation

MCQs

Total Questions : 41 | Page 3 of 5 pages

Question 21. What is short int in C programming?

Basic datatype of C
Qualifier
short is the qualifier and int is the basic datatype
All of the mentioned

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Answer: Option C. -> short is the qualifier and int is the basic datatype

None.

Question 22. What is the output of this C code? int main() { char chr; chr = 128; printf("%d\n", chr); return 0; }

128
-128
Depends on the compiler
None of the mentioned

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Answer: Option B. -> -128

signed char will be a negative number.
Output:
$ cc pgm2.c
$ a.out
-128

Question 23. Comment on the output of this C code? int main() { char c; int i = 0; FILE *file; file = fopen("test.txt", "w+"); fprintf(file, "%c", 'a'); fprintf(file, "%c", -1); fprintf(file, "%c", 'b'); fclose(file); file = fopen("test.txt", "r"); while ((c = fgetc(file)) != -1) printf("%c", c); return 0;. }

a
Infinite loop
Depends on what fgetc returns
Depends on the compiler

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Answer: Option A. -> a

None.
Output:
$ cc pgm3.c
$ a.out
a

Question 24. Comment on the output of this C code? int main() { float f1 = 0.1; if (f1 == 0.1f) printf("equal\n"); else printf("not equal\n"); }

equal
not equal
Output depends on compiler
None of the mentioned

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Answer: Option A. -> equal

0.1f results in 0.1 to be stored in floating point representations.
Output:
$ cc pgm5.c
$ a.out
equal

Question 25. Comment on the output of this C code? int main() { float f1 = 0.1; if (f1 == 0.1) printf("equal\n"); else printf("not equal\n"); }

equal
not equal
Output depends on compiler
None of the mentioned

Discuss Question

Answer: Option B. -> not equal

0.1 by default is of type double which has different representation than float resulting in inequality even after conversion.
Output:
$ cc pgm4.c
$ a.out
not equal

Question 26. What is the output of this C code (on a 32-bit machine)? int main() { int x = 10000; double y = 56; int *p = &x; double *q = &y; printf("p and q are %d and %d", sizeof(p), sizeof(q)); return 0; }