100+ C Language Solved MCQs

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Chapter: Introduction to C Language
1.

Which of the following is not a valid variable name declaration?

A. int __a3;
B. int __3a;
C. int __A3;
D. None of the mentioned
Answer» D. None of the mentioned
discuss (1)
2.

Which of the following is not a valid variable name declaration?

A. int _a3;
B. int a_3;
C. int 3_a;
D. int _3a
Answer» C. int 3_a;
discuss
3.

Why do variable names beginning with the underscore is not encouraged?

A. It is not standardized
B. To avoid conflicts since assemblers and loaders use such names
C. To avoid conflicts since library routines use such names
D. To avoid conflicts with environment variables of an operating system
Answer» C. To avoid conflicts since library routines use such names
discuss
4.

All keywords in C are in ____________

A. LowerCase letters
B. UpperCase letters
C. CamelCase letters
D. None of the mentioned
Answer» A. LowerCase letters
discuss
5.

Variable name resolution (number of significant characters for the uniqueness of variable) depends on ___________

A. Compiler and linker implementations
B. Assemblers and loaders implementations
C. C language
D. None of the mentioned
Answer» A. Compiler and linker implementations
discuss
6.

Which of the following is not a valid C variable name?

A. int number;
B. float rate;
C. int variable_count;
D. int $main;
Answer» D. int $main;
discuss
7.

Which of the following is true for variable names in C?

A. They can contain alphanumeric characters as well as special characters
B. It is not an error to declare a variable to be one of the keywords(like goto, static)
C. Variable names cannot start with a digit
D. Variable can be of any length
Answer» C. Variable names cannot start with a digit
discuss
8.

What is short int in C programming?

A. The basic data type of C
B. Qualifier
C. Short is the qualifier and int is the basic data type
D. All of the mentioned
Answer» C. Short is the qualifier and int is the basic data type
discuss
9.

The format identifier ‘%i’ is also used for _____ data type.

A. char
B. int
C. float
D. double
Answer» B. int
discuss
10.

Which data type is most suitable for storing a number 65000 in a 32-bit system?

A. signed short
B. unsigned short
C. long
D. int
Answer» B. unsigned short
discuss
11.

Which of the following is a User-defined data type?

A. typedef int Boolean;
B. typedef enum {Mon, Tue, Wed, Thu, Fri} Workdays;
C. struct {char name[10], int age};
D. all of the mentioned
Answer» D. all of the mentioned
discuss
12.

What is the size of an int data type?

A. 4 Bytes
B. 8 Bytes
C. Depends on the system/compiler
D. Cannot be determined
Answer» C. Depends on the system/compiler
discuss
13.

enum types are processed by _________

A. Compiler
B. Preprocessor
C. Linker
D. Assembler
Answer» A. Compiler
discuss
14.

Which of the following statement is false?

A. Constant variables need not be defined as they are declared and can be defined later
B. Global constant variables are initialized to zero
C. const keyword is used to define constant values
D. You cannot reassign a value to a constant variable
Answer» A. Constant variables need not be defined as they are declared and can be defined later
discuss
15.

Which of the following declaration is not supported by C?

A. String str;
B. char *str;
C. float str = 3e2;
D. Both String str; & float str = 3e2;
Answer» A. String str;
discuss
16.

Which of the following declaration is illegal?

A. char *str = “string Contents”;
B. char str[] = “string Contents””;
C. char str[20] = “string Contents””;
D. char[] str = “string Contents””;
Answer» D. char[] str = “string Contents””;
discuss
17.

Which keyword is used to prevent any changes in the variable within a C program?

A. immutable
B. mutable
C. const
D. volatile
Answer» C. const
discuss
18.

Which of the following is not a pointer declaration?

A. char a[10];
B. char a[] = {‘1’, ‘2’, ‘3’, ‘4’};
C. char *str;
D. char a;
Answer» D. char a;
discuss
19.

Which of the following statement is false?

A. A variable defined once can be defined again with different scope
B. A single variable cannot be defined with two different types in the same scope
C. A variable must be declared and defined at the same time
D. A variable refers to a location in memory
Answer» C. A variable must be declared and defined at the same time
discuss
20.

A variable declared in a function can be used in main().

A. True
B. False
C. True if it is declared static
D. None of the mentioned
Answer» B. False
discuss
21.

What is the precedence of arithmetic operators (from highest to lowest)?

A. %, *, /, +, –
B. %, +, /, *, –
C. +, -, %, *, /
D. %, +, -, *, /
Answer» A. %, *, /, +, –
discuss
22.

Which of the following is not an arithmetic operation?

A. a * = 10;
B. a / = 10;
C. a ! = 10;
D. a % = 10;
Answer» C. a ! = 10;
discuss
23.

Which of the following data type will throw an error on modulus operation(%)?

A. char
B. short
C. int
D. float
Answer» D. float
discuss
24.

Which among the following are the fundamental arithmetic operators, i.e, performing the desired operation can be done using that operator only?

A. +, –
B. +, -, %
C. +, -, *, /
D. +, -, *, /, %
Answer» A. +, –
discuss
25.

Are logical operator sequence points?

A. True
B. False
C. Depends on the compiler
D. Depends on the standard
Answer» A. True
discuss
26.

Do logical operators in the C language are evaluated with the short circuit?

A. True
B. False
C. Depends on the compiler
D. Depends on the standard
Answer» A. True
discuss
27.

What is the result of logical or relational expression in C?

A. True or False
B. 0 or 1
C. 0 if an expression is false and any positive number if an expression is true
D. None of the mentioned
Answer» B. 0 or 1
discuss
28.

Relational operators cannot be used on ____________

A. structure
B. long
C. strings
D. float
Answer» A. structure
discuss
29.

Which among the following is NOT a logical or relational operator?

A. !=
B. ==
D. =
Answer» D. =
discuss
30.

What is the type of the following assignment expression if x is of type float and y is of type int? y = x + y;

A. int
B. float
C. there is no type for an assignment expression
D. double
Answer» A. int
discuss (1)
31.

What will be the value of the following assignment expression? (x = foo())!= 1 considering foo() returns 2

A. 2
B. True
C. 1
D. 0
Answer» A. 2
discuss
32.

Operation “a = a * b + a” can also be written as ___________

A. a *= b + 1;
B. (c = a * b)!=(a = c + a);
C. a = (b + 1)* a;
D. All of the mentioned
Answer» D. All of the mentioned
discuss
33.

What will be the final value of c in the following C statement? (Initial value: c = 2) c <<= 1;

A. c = 1;
B. c = 2;
C. c = 3;
D. c = 4;
Answer» D. c = 4;
discuss
34.

In expression i = g() + f(), first function called depends on __________

A. Compiler
B. Associativiy of () operator
C. Precedence of () and + operator
D. Left to write of the expression
Answer» A. Compiler
discuss
35.

Which operators of the following have same precedence? P. "!=", Q. "+=", R. "<<="

A. P and Q
B. Q and R
C. P and R
D. P, Q and R
Answer» B. Q and R
discuss
36.

Comment on the following statement n = 1; printf("%d, %dn", 3*n, n++);

A. Output will be 3, 2
B. Output will be 3, 1
C. Output will be 6, 1
D. Output is compiler dependent
Answer» D. Output is compiler dependent
discuss
37.

Which is correct representation of C statement? e = a * b + c / d * f;

A. e = (a * (b +(c /(d * f))));
B. e = ((a * b) + (c / (d * f)));
C. e = ((a * b) + ((c / d)* f));
D. Both e = ((a * b) + (c / (d * f))); and e = ((a * b) + ((c / d)* f));
Answer» D. Both e = ((a * b) + (c / (d * f))); and e = ((a * b) + ((c / d)* f));
discuss
38.

While swapping 2 no’ what at precautions to be taken care? b = (b / a); a = a * b; b = a / b;

A. Data type should be either of short, int and long
B. Data type should be either of float and double
C. All data types are accepted except for (char *)
D. This code doesn’t swap 2 numbers
Answer» B. Data type should be either of float and double
discuss
39.

function tolower(c) defined in library <ctype.h> works for ___________

A. Ascii character set
B. Unicode character set
C. Ascii and utf-8 but not EBCDIC character set
D. Any character set
Answer» D. Any character set
discuss
40.

Which type of conversion is NOT accepted?

A. From char to int
B. From float to char pointer
C. From negative int to char
D. From double to char
Answer» B. From float to char pointer
discuss
41.

Which of the following type-casting have chances for wrap around?

A. From int to float
B. From int to char
C. From char to short
D. From char to int
Answer» B. From int to char
discuss
42.

Which of the following typecasting is accepted by C?

A. Widening conversions
B. Narrowing conversions
C. Widening & Narrowing conversions
D. None of the mentioned
Answer» C. Widening & Narrowing conversions
discuss
43.

When do you need to use type-conversions?

A. The value to be stored is beyond the max limit
B. The value to be stored is in a form not supported by that data type
C. To reduce the memory in use, relevant to the value
D. All of the mentioned
Answer» D. All of the mentioned
discuss
44.

What is the scope of an external variable?

A. Whole source file in which it is defined
B. From the point of declaration to the end of the file in which it is defined
C. Any source file in a program
D. From the point of declaration to the end of the file being compiled
Answer» D. From the point of declaration to the end of the file being compiled
discuss
45.

What is the scope of a function?

A. Whole source file in which it is defined
B. From the point of declaration to the end of the file in which it is defined
C. Any source file in a program
D. From the point of declaration to the end of the file being compiled
Answer» D. From the point of declaration to the end of the file being compiled
discuss
46.

In the standard library of C programming language, which of the following header file is designed for basic mathematical operations?

A. math.h
B. conio.h
C. dos.h
D. stdio.h
Answer» A. math.h
discuss
47.

Which of the following statements should be used to obtain a remainder after dividing 3.14 by 2.1 ?

A. rem = 3.14 % 2.1;
B. rem = modf(3.14, 2.1);
C. rem = fmod(3.14, 2.1);
D. Remainder cannot be obtain in floating point division.
Answer» C. rem = fmod(3.14, 2.1);
discuss
48.

By default a real number is treated as a

A. A.float
B. B.double
C. C.long double
D. D. far double
Answer» B. B.double
discuss
Chapter: Managing IO Operations
49.

Which among the following is the odd one out?

A. printf
B. fprintf
C. putchar
D. scanf
Answer» D. scanf
discuss
50.

For a typical program, the input is taken using _________

A. scanf
B. Files
C. Command-line
D. All of the mentioned
Answer» D. All of the mentioned
discuss
51.

What does the following command line signify? prog1 prog2

A. It runs prog1 first, prog2 second
B. It runs prog2 first, prog1 second
C. It runs both the programs, pipes output of prog1 to input of prog2
D. It runs both the programs, pipes output of prog2 to input of prog1
Answer» C. It runs both the programs, pipes output of prog1 to input of prog2
discuss
52.

What is the default return-type of getchar()?

A. char
B. int
C. char *
D. reading character doesn’t require a return-type
Answer» B. int
discuss
53.

What is the value of EOF?

A. -1
B. 0
C. 1
D. 10
Answer» A. -1
discuss
54.

What is the use of getchar()?

A. The next input character each time it is called
B. EOF when it encounters end of file
C. The next input character each time it is called EOF when it encounters end of file
D. None of the mentioned
Answer» C. The next input character each time it is called EOF when it encounters end of file
discuss
55.

Which of the following statement is true?

A. The symbolic constant EOF is defined in <stdio.h>
B. The value is -1
C. The symbolic constant EOF is defined in <stdio.h> & value is -1
D. Only value is -1
Answer» C. The symbolic constant EOF is defined in <stdio.h> & value is -1
discuss
56.

What is the return value of putchar()?

A. The character written
B. EOF if an error occurs
C. Nothing
D. Both character written & EOF if an error occurs
Answer» D. Both character written & EOF if an error occurs
discuss
57.

Escape sequences are prefixed with ________

A. %
B. /
C. ”
D. None of the mentioned
Answer» D. None of the mentioned
discuss
58.

What is the purpose of sprintf?

A. It prints the data into stdout
B. It writes the formatted data into a string
C. It writes the formatted data into a file
D. None of the mentioned
Answer» B. It writes the formatted data into a string
discuss
59.

The syntax to print a % using printf statement can be done by ________

A. %
B. \%
C. ‘%’
D. %%
Answer» D. %%
discuss
60.

What are the Properties of the first argument of a printf() functions?

A. It is defined by a user
B. It keeps the record of the types of arguments that will follow
C. There may no be first argument
D. None of the mentioned
Answer» B. It keeps the record of the types of arguments that will follow
discuss
61.

Which of the following function with ellipsis are illegal?

A. void func(…);
B. void func(int, …);
C. void func(int, int, …);
D. none of the mentioned
Answer» A. void func(…);
discuss
62.

Which of the following data-types are promoted when used as a parameter for an ellipsis?

A. char
B. short
C. int
D. none of the mentioned
Answer» A. char
discuss
63.

Which header file includes a function for variable number of arguments?

A. stdlib.h
B. stdarg.h
C. ctype.h
D. both stdlib.h and stdarg.h
Answer» A. stdlib.h
discuss
64.

Which of the following macro extracts an argument from the variable argument list (ie ellipsis) and advance the pointer to the next argument?

A. va_list
B. va_arg
C. va_end
D. va_start
Answer» B. va_arg
discuss
65.

The type va_list in an argument list is used ________

A. To declare a variable that will refer to each argument in turn;
B. For cleanup
C. To create a list
D. There is no such type
Answer» A. To declare a variable that will refer to each argument in turn;
discuss
66.

In a variable length argument function, the declaration “…” can _______

A. Appear anywhere in the function declaration
B. Only appear at the end of an argument list
C. Nothing
D. None of the mentioned
Answer» B. Only appear at the end of an argument list
discuss
67.

Each call of va_arg _______

A. Returns one argument
B. Steps va_list variable to the next
C. Returns one argument & Steps va_list variable to the next
D. None of the mentioned
Answer» C. Returns one argument & Steps va_list variable to the next
discuss
68.

The standard header _______ is used for variable list arguments (…) in C.

A. <stdio.h >
B. <stdlib.h>
C. <math.h>
D. <stdarg.h>
Answer» D. <stdarg.h>
discuss
69.

What is the purpose of va_end?

A. Cleanup is necessary
B. Must be called before the program returns
C. Cleanup is necessary & Must be called before the program returns
D. None of the mentioned
Answer» C. Cleanup is necessary & Must be called before the program returns
discuss
70.

Which of the following is NOT a delimiter for an input in scanf?

A. Enter
B. Space
C. Tab
D. None of the mentioned
Answer» D. None of the mentioned
discuss
71.

If the conversion characters of int d, i, o, u and x are preceded by h, it indicates?

A. A pointer to int
B. A pointer to short
C. A pointer to long
D. A pointer to char
Answer» B. A pointer to short
discuss
72.

Which of the following doesn’t require an & for the input in scanf()?

A. char name[10];
B. int name[10];
C. float name[10];
D. all of the mentioned
Answer» A. char name[10];
discuss
73.

Which of the following is an invalid method for input?

A. scanf(“%d%d%d”,&a, &b, &c);
B. scanf(“%d %d %d”, &a, &b, &c);
C. scanf(“Three values are %d %d %d”,&a,&b,&c);
D. none of the mentioned
Answer» D. none of the mentioned
discuss
74.

Which of the following represents the function for scanf()?

A. void scanf(char *format, …)
B. int scanf(char *format, …)
C. char scanf(int format, …)
D. char *scanf(char *format, …)
Answer» B. int scanf(char *format, …)
discuss
75.

What does scanf() function return?

A. Number of successfully matched and assigned input items
B. Nothing
C. Number of characters properly printed
D. Error
Answer» A. Number of successfully matched and assigned input items
discuss
76.

The conversion characters d, i, o, u, and x may be preceded by h in scanf() to indicate?

A. A pointer to short
B. A pointer to long
C. Nothing
D. Error
Answer» A. A pointer to short
discuss
77.

The syntax of printf() function is printf(“control string”, variable list) ;what is the prototype of the control string?

A. %[flags][.precision][width][length]specifier
B. %[flags][length][width][.precision]specifier
C. %[flags][width][.precision][length]specifier
D. %[flags][.precision][length][width]specifier
Answer» C. %[flags][width][.precision][length]specifier
discuss
78.

The parameter control string in the printf () is a C String that contains text to be __________

A. taken from a standard output device
B. written on to the standard output device
C. received from the standard output device
D. nothing can be said
Answer» B. written on to the standard output device
discuss
79.

Output justification such as decimal point, numerical sign, trailing zeros or octal are specified.

A. specifier
B. flags
C. precision
D. decimal
Answer» B. flags
discuss
80.

What symbol is used to Left-justify within the data given field width?

A. -(minus sign)
B. +(plus sign)
C. #
D. 0
Answer» A. -(minus sign)
discuss
81.

What specifies the minimum number of characters to print after being padded with zeros or blank spaces?

A. flags
B. length
C. width
D. precision
Answer» C. width
discuss
82.

The maximum number of characters to be printed is specified by __________

A. precision
B. width
C. length
D. flags
Answer» A. precision
discuss
83.

________is used to define the type and the interpretation of the value of the corresponding argument.

A. precision
B. specifiers
C. flags
D. decimal
Answer» B. specifiers
discuss
84.

A conversion specification %7.4f means ____________

A. print a floating point value of maximum 7 digits where 4 digits are allotted for the digits after the decimal point
B. print a floating point value of maximum 4 digits where 7digits are allotted for the digits after the decimal point
C. print a floating point value of maximum 7 digits
D. print a floating point value of minimum 7 digits where 4 digits are allotted for the digits after the decimal point
Answer» A. print a floating point value of maximum 7 digits where 4 digits are allotted for the digits after the decimal point
discuss
85.

Choose the correct description for control string %-+7.2f.

A. – means display the sign, + means left justify, 7 specifies the width and 2 specifies the precision
B. – means left justify, + means display the sign, 7 specifies the width and 2 specifies the precision
C. – means display the sign, + means left justify, 7 specifies the precision and 2 specifies the width
D. – means left justify, + means display the sign, 7 specifies the precision and 2 specifies the width
Answer» B. – means left justify, + means display the sign, 7 specifies the width and 2 specifies the precision
discuss
86.

What error is generated on placing an address operator with a variable in the printf statement?

A. compile error
B. run-time error
C. logical error
D. no error
Answer» B. run-time error
discuss
87.

If by mistake you specify more number of arguments, the excess arguments will ____________

A. be ignored
B. produce compile error
C. produce run-time error
D. produce logical error
Answer» A. be ignored
discuss
88.

What happens when zero flag is used with left justification?

A. data is padded with zeros
B. zero flag is ignored
C. data is padded with blank spaces
D. will give error
Answer» B. zero flag is ignored
discuss
89.

For floating point numbers, the precision flag specifies the number of decimal places to be printed. When no precision modifier is specified, printf() prints _______

A. six decimal positions
B. five decimal positions
C. four decimal positions
D. three decimal positions
Answer» A. six decimal positions
discuss
90.

What will the given code result in printf(“\n you are\”awesome \" ");?

A. compile error
B. run-time error
C. you are "awesome"
D. you are awesome
Answer» C. you are "awesome"
discuss
91.

What will be the output for the given code printf(“\n The number is %07d”,1212);

A. The number is 0001212
B. The number is 1212
C. The number is 1212
D. The number is 1212000
Answer» A. The number is 0001212
discuss
92.

The syntax of the scanf() is scanf(“control string “, arg1,arg2,arg3,….,argn); the prototype of control string is ____________

A. [=%[width][modifiers]type=]
B. [=%[modifiers][width]type=]
C. [=%[width] [modifiers]]
D. [width][modifiers]
Answer» A. [=%[width][modifiers]type=]
discuss
93.

What is the use of symbol * in the control string as shown [=%[*][width] [modifiers] type=]?

A. * is optional and used when the data should be read from the stream but ignored
B. * is not optional, used to read data from the stream but it is not ignored
C. * is not optional, it is used to read data stream but ignored
D. * is optional and used to read data from stream but it is not ignored
Answer» A. * is optional and used when the data should be read from the stream but ignored
discuss
94.

What action is carried out by scanf if a user enters any blank spaces, tabs, and newlines?

A. consider as input
B. ignores it
C. produces error
D. nothing can be said
Answer» B. ignores it
discuss
95.

What error will generate if the read and write parameters are not separated by commas?

A. run-time error
B. compile error
C. logical error
D. no error
Answer» B. compile error
discuss
96.

_____ is an optional argument that gives the maximum number of characters to be read.

A. modifiers
B. width
C. precision
D. length
Answer» B. width
discuss
97.

Explain the format string "%5d%s %c"

A. five characters as a decimal integer, then reads the remaining as a string and then scans the first non-whitespace character
B. compile error
C. run-time error
D. read first five characters as a decimal and ignore the rest
Answer» A. five characters as a decimal integer, then reads the remaining as a string and then scans the first non-whitespace character
discuss
98.

Select the correct value of i from given options i=scanf("%d %d", &a, &b);

A. 1
B. 2
C. 3
D. No value assigned
Answer» B. 2
discuss
99.

If the user enters 1 3.2 s, what value will be returned by the scanf()?scanf("%d %f %c", &s1, &s2, &s3);

A. 1
B. 2
C. 3
D. No return value
Answer» C. 3
discuss
100.

If the user enters 1 s 3.2, what value will be returned by the scanf()?scanf("%d %f %c", &a, &b, &c);

A. 1
B. 2
C. 3
D. no return value
Answer» A. 1
discuss

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