Programming in C
Questions:
1. Write a program to demonstrate working of enum in C.
2. Write a C program to swap 2 values using call by reference.
3. Write a C program to demonstrate Example of recursion
4. Write a C program to illustrate pointers.
5. Write a C program to overcome the problem of a dangling pointer
6. Write a C program to store and display the student details using structure?
7. Can we compile a program without main() function in C?
8. Write a program to reverse a given number in C?
9. Write a C program to check palindrome number?
10. Write a C program to convert a number to a string with the help of sprintf()
function?
Program with Output:
1. Write a program to demonstrate working of enum in C.
2. #include <stdio.h>
3. enum week { Mon, Tue, Wed, Thur, Fri, Sat, Sun };
4.
5. int main()
6. {
7.
enum week day;
8.
day = Wed;
9.
printf("%d", day);
10. return 0;
11. }
Output
2
2. Write a program to swap 2 values using call by reference:
1. #include <stdio.h>
2. void change(int*,int*);
3. int main()
4. {
5.
int a=10,b=20;
6.
change(&a,&b); // calling a function by passing references of variables.
7.
printf("Value of a is: %d",a);
8.
printf("\n");
9.
printf("Value of b is: %d",b);
10.
return 0;
11. }
12. void change(int *x,int *y)
13. {
14.
*x=13;
15.
*y=17;
16. }
Output:
Value of a is: 13
Value of b is: 17
3. Write a program to demonstrate Example of recursion
1. #include <stdio.h>
2. int calculate_fact(int);
3. int main()
4. {
5.
int n=5,f;
6.
f=calculate_fact(n); // calling a function
7.
printf("factorial of a number is %d",f);
8.
return 0;
9. }
10. int calculate_fact(int a)
11. {
12. if(a==1)
13. {
14.
return 1;
15. }
16. else
17. return a*calculate_fact(a-1); //calling a function recursively.
18.
}
Output:
factorial of a number is 120
4. Write a program to illustrate pointers
1.
#include <stdio.h>
2. int main()
3. {
4.
int *p; //pointer of type integer.
5.
int a=5;
6.
p=&a;
7.
printf("Address value of 'a' variable is %u",p);
8.
return 0;
9. }
Output:
Address value of 'a' variable is 428781252
5. Write a program to overcome the problem of a dangling pointer
1.
#include<stdio.h>
2.
void main()
3.
{
4.
int *ptr = malloc(constant value); //allocating a memory space.
5.
free(ptr); //ptr becomes a dangling pointer.
6.
ptr=NULL; //Now, ptr is no longer a dangling pointer.
}
6. Write a program to store and display the student details using structure?
1. #include <stdio.h>
2. struct student
3. {
4.
char name[10];
5.
int age;
6. }s1;
// structure members declaration.
//structure variable
7. int main()
8. {
9.
printf("Enter the name");
10.
scanf("%s",s1.name);
11.
printf("\n");
12.
printf("Enter the age");
13.
scanf("%d",&s1.age);
14.
printf("\n");
15.
printf("Name and age of a student: %s,%d",s1.name,s1.age);
16.
return 0;
17. }
Output:
Enter the name shikha
Enter the age 26
Name and age of a student: shikha,26
7. Can we compile a program without main() function?
Yes, we can compile, but it can't be executed.
But, if we use #define, we can compile and run a C program without using the main()
function.
1. #include<stdio.h>
2. #define start main
3. void start() {
4.
printf("Hello");
5. }
8. Write a program to reverse a given number in C?
1. #include<stdio.h>
2. #include<conio.h>
3. main()
4. {
5. int n, reverse=0, rem;
//declaration of variables.
6. clrscr(); // It clears the screen.
7. printf("Enter a number: ");
8. scanf("%d", &n);
9. while(n!=0)
10. {
11.
rem=n%10;
12.
reverse=reverse*10+rem;
13.
n/=10;
14. }
15. printf("Reversed Number: %d",reverse);
16. getch(); // It reads a character from the keyword.
17. }
Output:
Enter a number: 123
Reversed Number: 321
9. Write a program to check palindrome number in C Programming?
1. #include<stdio.h>
2. #include<conio.h>
3. main()
4. {
5. int n,r,sum=0,temp;
6. clrscr();
7. printf("enter the number=");
8. scanf("%d",&n);
9. temp=n;
10. while(n>0)
11. {
12. r=n%10;
13. sum=(sum*10)+r;
14. n=n/10;
15. }
16. if(temp==sum)
17. printf("palindrome number ");
18. else
19. printf("not palindrome");
20. getch();
21. }
Output:
enter the number=151
palindrome number
enter the number=5621
not palindrome number
10. Write a program to convert a number to a string with the help of sprintf()
function
#include <stdio.h>
#include <string.h>
int main()
{
char res[20];
float a = 32.23;
sprintf(res, "%f", a);
printf("\nThe string for the num is %s", res);
return 0;
}
Output
The string for the num is 32.230000