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Difficulty: All Easy Medium Hard 111–120 of 309
Topics in Computer Knowledge
All C Programming 200 Database/SQL 100
Q.111 Medium C Programming
What is the output of the following code?
int x = 5;
int y = ++x;
printf("%d %d", x, y);
A 5 5
B 6 6
C 6 5
D 5 6
Correct Answer:  B. 6 6
EXPLANATION

++x is pre-increment, which increments x before assignment. So x becomes 6, then y is assigned 6. Both x and y are 6.

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Q.112 Easy C Programming
What is the output of the following C code?
int main() {
int a = 10;
printf("%d", a += 5);
return 0;
}
A 10
B 15
C 5
D Compilation Error
Correct Answer:  B. 15
EXPLANATION

The += operator adds 5 to a (a = a + 5 = 10 + 5 = 15), and printf prints the updated value 15.

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Q.113 Easy C Programming
In the expression: int arr[3][3]; arr[1][2] = 5; What is being accessed?
A Element in row 1, column 2
B Element in row 2, column 3
C Element in row 2, column 1
D Invalid access - syntax error
Correct Answer:  A. Element in row 1, column 2
EXPLANATION

In C, array indices are 0-based. arr[1][2] refers to the element in the second row (index 1) and third column (index 2) of the 2D array.

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Q.114 Easy C Programming
Which function is used to read a single character from standard input?
A scanf()
B getchar()
C gets()
D fgetc()
Correct Answer:  B. getchar()
EXPLANATION

getchar() reads a single character from standard input (stdin). While fgetc() can also read a character, getchar() is the standard dedicated function for this purpose.

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Q.115 Hard C Programming
What will be the output of: int x = 5; int y = x++ + ++x; ?
A y = 11
B y = 12
C y = 10
D Undefined behavior
Correct Answer:  D. Undefined behavior
EXPLANATION

This expression involves modifying the same variable (x) multiple times without an intervening sequence point. This is undefined behavior in C, and the result cannot be predicted reliably.

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Q.116 Hard C Programming
Which of the following will correctly allocate memory for an array of 10 integers?
A int *arr = malloc(10);
B int *arr = malloc(10 * sizeof(int));
C int arr[10] = malloc(10);
D int *arr = calloc(10);
Correct Answer:  B. int *arr = malloc(10 * sizeof(int));
EXPLANATION

malloc() allocates memory in bytes. To allocate for 10 integers, we need 10 * sizeof(int) bytes. Option A allocates only 10 bytes, insufficient for 10 integers.

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Q.117 Hard C Programming
Consider the code: int *p; int arr[5]; p = arr; What does p[2] represent?
A The address of arr[2]
B The value at arr[2]
C The pointer itself
D A syntax error
Correct Answer:  B. The value at arr[2]
EXPLANATION

When p points to arr, p[2] is equivalent to *(p+2) and accesses the value at arr[2]. Pointers and array names decay to pointers, and pointer indexing retrieves the value.

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Q.118 Hard C Programming
What is the difference between #include and #include "stdio.h"?
A They are identical
B searches in system directories, "" searches in current directory first
C "" is for user-defined headers, is for system headers
D Both B and C are correct
Correct Answer:  D. Both B and C are correct
EXPLANATION

Using <> tells the compiler to search in standard system directories. Using "" tells it to search in the current directory first, then system directories. Generally, "" is used for user-defined headers and <> for standard library headers.

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Q.119 Medium C Programming
How is a two-dimensional array typically stored in memory in C?
A Column-major order
B Random order
C Row-major order
D Scattered order
Correct Answer:  C. Row-major order
EXPLANATION

C uses row-major order to store 2D arrays in memory. The elements are stored row by row sequentially in memory.

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Q.120 Medium C Programming
Which loop construct will execute at least once even if the condition is false?
A while loop
B for loop
C do-while loop
D All of the above
Correct Answer:  C. do-while loop
EXPLANATION

The do-while loop executes the body first and then checks the condition, ensuring at least one execution. while and for loops check the condition first.

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