Modify the value pointed to by x to increase by 1;
}
int main {
int a = 10;
increment(&a);
printf("%d", a);
return 0;
}
- Compilation error
Explanation:
The correct answer is option (b). The rise in the rate function updates the value of a through the application of call by reference. After incorporating one to the value of a, the result is 11.
2. What would be the main benefit using call by referenced as opposed to call by value?
- It allows the function to modify local copies of the arguments.
- It allows the function to return multiple values.
- It ensures the original arguments are not changed.
- It prevents the function from modifying the arguments.
Explanation:
The correct answer is option (b). Through modifying the given parameters, an algorithm that makes use of call by reference could give back a number of results in in addition to changing the initially set variables. On the other hand, Call by value restricts modification to localized representations of the inputs.
3. Given the following function, what will be the output of the main function?
Define a function named setToZero that sets the value pointed to by x to 0.
int main {
int a = 5;
setToZero(&a);
printf("%d", a);
return 0;
}
- Compilation error
- Undefined behavior
Explanation:
The correct answer is option (a). The setToZero function uses call by reference to set the value of a to 0. Since it modifies the actual variable a through its address, the output will be 0.
4. Which of the following is true for call by value?
- The argument which is handed in when executing the function might have had had its significance updated by the function.
- The numerical value of the argument being used has been copied to the function.
- The argument's address is sent to the function.
- The given function has several alternative returns.
Explanation:
The correct answer is option (b). In call by value, the function receives a copy of the argument's value. Changes made to this copy do not affect the original variable.
5. What is the output of the following code?
Create a function called modify that assigns the value pointed to by x as 100.
void main {
int number = 50;
changeValue(&number);
printf("number = %d", number);
return 0;
}
- a = 50
- a = 0
- a = 100
- Compilation error
Explanation:
The correct answer is option (c). The modify function uses call by reference to change the value of a. The value of a is set to 100 through the pointer, so the output is "a = 100".
6. What is the output of the following code?
void changeValue(int *ptr) {
*ptr = 10;
}
void adjust(int value) {
value = 20;
}
Compilation error occurs when the code cannot be successfully compiled due to syntax errors or other issues.
Undefined behavior happens when the program executes code that results in unpredictable outcomes, typically due to accessing uninitialized variables or violating language rules.
Explanation:
The correct answer is option (a). The func function is called by value, so the change to x inside func does not affect the original variable a. Therefore, the value of a remains 10.
- Which of the following is true about Call by Value in C?
- It is more efficient than Call by Reference.
- It cannot be used with primitive data types.
- Changes made to the parameter inside the function reflect in the original data.
- It passes the address of the data to the function.
Explanation:
The correct answer is option (c). Call by Value passes a copy of the parameter to the function. Changes made to this copy inside the function do not affect the original data outside the function.
- Consider the following function prototype in C: void swap(int a, int b); Which technique does this function use?
- Call by Value
- Call by Reference
- Both Call by Value and Call by Reference
- None of the above
Explanation:
The accurate choice is alternative (b). The function prototype specifies that the swap function takes integer pointers (int a, int b), enabling it to alter the values of a and b directly in the memory.
It is typically used for primitive data types like integers and floats. On the other hand, Call by Reference passes the address of the actual data (using pointers in C), allowing functions to directly access and modify the original data. This method is advantageous when dealing with large data structures or when modifications need to be reflected globally throughout the program. Understanding when to use each technique is crucial for efficient and effective programming in C.
- Which of the following statements is true regarding parameter passing in C?
- Only Call by Value is supported in C.
- Only Call by Reference is supported in C.
- C supports both Call by Value and Call by Reference.
- C supports neither Call by Value nor Call by Reference.
Explanation:
The accurate choice is alternative (c). In the C programming language, functions can be invoked using either Call by Value (where duplicates of the arguments are transferred) or Call by Reference (where pointers are used to pass the addresses of the arguments).