C- Const Question and Answer

C- Const Question and Answer
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;
}
  • 128
  • Garbage value
  • Error
  • 0
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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;
}

  • Error: RValue required
  • Error: cannot convert from 'const int *' to 'int *const'
  • Error: LValue required in strcpy
  • No error
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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;
}

  • Address of i Address of j
  • 10 223
  • Error: cannot convert parameter 1 from 'const int **' to 'int **'
  • Garbage value
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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;
}

  • 5
  • 10
  • Error
  • Garbage value
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5. What will be the output of the program in TurboC?

#include<stdio.h>
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;
}
  • i= FFE2 ptr=12 j=FFE4 ptr=24
  • i= FFE4 ptr=10 j=FFE2 ptr=20
  • i= FFE0 ptr=20 j=FFE1 ptr=30
  • Garbage value
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6. What will be the output of the program?

#include<stdio.h>

int main()
{
    const char *s = "";
    char str[] = "Hello";
    s = str;
    while(*s)
        printf("%c", *s++);

    return 0;
}
  • Error
  • H
  • Hello
  • Hel
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7. What will be the output of the program?
#include<stdio.h>
int get();

int main()
{
    const int x = get();
    printf("%d", x);
    return 0;
}
int get()
{
    return 20;
}
  • Garbage value
  • Error
  • 20
  • 0
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8. What will be the output of the program (in Turbo C)?

#include<stdio.h>

int fun(int *f)
{
    *f = 10;
    return 0;
}
int main()
{
    const int arr[5] = {1, 2, 3, 4, 5};
    printf("Before modification arr[3] = %d", arr[3]);
    fun(&arr[3]);
    printf("\nAfter modification arr[3] = %d", arr[3]);
    return 0;
}
  • Before modification arr[3] = 4 After modification arr[3] = 10
  • Error: cannot convert parameter 1 from const int * to int *
  • Error: Invalid parameter
  • Before modification arr[3] = 4
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9. What will be the output of the program?
#include<stdio.h>

int main()
{
    const int i=0;
    printf("%d\n", i++);
    return 0;
}

  • 10
  • 11
  • No output
  • Error: ++needs a value
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10. What will be the output of the program?
#include<stdio.h>

int main()
{
    const c = -11;
    const int d = 34;
    printf("%d, %d\n", c, d);
    return 0;
}

  • Error
  • -11, 34
  • 11, 34
  • None of these
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