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			Const Questions And Answers.  
		
  		   
          
		   
| 1. | What will be the output of the program? | 
		|  | 
#include<stdio.h>
int main()
{
    int y=128;
    const int x=y;
    printf("%d\n", x);
    return 0;
}
 | 
		|  | A. | 128 | 
|  | B. | Garbage value | 
|  | C. | Error | 
|  | D. | 0 | 
|  |  | 
   
		
		    
			   |  | Answer:  Option  A | 
|  | 
|  | 
		    
|  | Explanation: | 
		    
		|  | Step 1: int y=128; The variable 'y' is declared as an integer type and initialized to value "128". Step 2: const int x=y; The constant variable 'x' is declared as an integer and it is initialized with the variable 'y' value. Step 3: printf("%d\n", x); It prints the value of variable 'x'. Hence the output of the program is "128" | 
|  | See More Information | 
|  | 
|  | 
		    |  | Tutorial Link: | 
		
		
			Published by:Michael Daani 
		 
| 2. | What will be the output of the program ? | 
		|  | 
#include<stdio.h>
#include<stdlib.h>
union employee
{
    char name[15];
    int age;
    float salary;
};
const union employee e1;
int main()
{
    strcpy(e1.name, "K");
    printf("%s %d %f", e1.name, e1.age, e1.salary);
    return 0;
}
 | 
		|  | A. | Error: RValue required | 
|  | B. | Error: LValue required in strcpy | 
|  | C. | Error: cannot convert from 'const int *' to 'int *const' | 
|  | D. | No Error | 
|  |  | 
   
		
		    
			   |  | Answer:  Option  D | 
|  | 
|  | 
		    
|  | Explanation: | 
		    
		|  | The output will be (in 16-bit platform DOS): K 75 0.000000 | 
|  | See More Information | 
|  | 
|  | 
		    |  | Tutorial Link: | 
		
		
			Published by:Michael Daani 
		 
| 3. | What will be the output of the program? | 
		|  | 
#include<stdio.h>
int fun(int **ptr);
int main()
{
    int i=10;
    const int *ptr = &i;
    fun(&ptr);
    return 0;
}
int fun(int **ptr)
{
    int j = 223;
    int *temp = &j;
    printf("Before changing ptr = %5x\n", *ptr);
    const *ptr = temp;
    printf("After changing ptr = %5x\n", *ptr);
    return 0;
}
 | 
		|  | A. | Address of i       Address of j | 
|  | B. | 10     223 | 
|  | C. | Garbage Value | 
|  | D. | Error: cannot convert parameter 1 from 'const int **' to 'int **' | 
|  |  | 
   
		
			Published by:Michael Daani 
		 
| 4. | What will be the output of the program? | 
		|  | 
#include<stdio.h>
int main()
{
    const int x=5;
    const int *ptrx;
    ptrx = &x;
    *ptrx = 10;
    printf("%d\n", x);
    return 0;
}
 | 
		|  | A. | 5 | 
|  | B. | 10 | 
|  | C. | Garbage Value | 
|  | D. | Error | 
|  |  | 
   
		
		    
			   |  | Answer:  Option  D | 
|  | 
|  | 
		    
|  | Explanation: | 
		    
		|  | Step 1: const int x=5; The constant variable x is declared as an integer data type and initialized with value '5'. Step 2: const int *ptrx; The constant variable ptrx is declared as an integer pointer. Step 3: ptrx = &x; The address of the constant variable x is assigned to integer pointer variable ptrx. Step 4: *ptrx = 10; Here we are indirectly trying to change the value of the constant vaiable x. This will result in an error. To change the value of const variable x we have to use *(int *)&x = 10; | 
|  | See More Information | 
|  | 
|  | 
		    |  | Tutorial Link: | 
		
		
			Published by:Michael Daani 
		 
| 5. | What will be the output of the program? | 
		|  | 
int fun(int **ptr);
int main()
{
    int i=10, j=20;
    const int *ptr = &i;
    printf(" i = %5X", ptr);
    printf(" ptr = %d", *ptr);
    ptr = &j;
    printf(" j = %5X", ptr);
    printf(" ptr = %d", *ptr);
    return 0;
}
 | 
		|  | A. | i= FFE2 ptr=12 j=FFE4 ptr=24 | 
|  | B. | i= FFE4 ptr=10 j=FFE2 ptr=20 | 
|  | C. | i= FFE0 ptr=20 j=FFE1 ptr=30 | 
|  | D. | Garbage value | 
|  |  | 
   
		
			Published by:Michael Daani