c programming 2017

2nd Semester

Year 2017

2.Write a program to add four integer taken from user
 

#include<stdio.h>
void main()
{
      int a,b,c,d,s;
      printf("Enter four integers:\n");
      scanf("%d%d%d%d",&a,&b,&c,&d);
      s = a+b+c+d;
      printf("The sum of given four integers = %d.",s);
}
Output:
Enter four integers:
1
2
3
4
The sum of given four integers = 10.

3. Explain dynamic memory allocation with example
The concept of dynamic memory allocation in c language enables the C programmer to allocate memory at runtime.
Dynamic memory allocation in c language is possible by 4 functions of stdlib.h header file.
malloc():-allocates single block of requested memory.
The syntax of malloc() function is given below:
ptr=(cast-type*)malloc(byte-size)
calloc():-allocates multiple block of requested memory.
The syntax of calloc() function is given below:
ptr=(cast-type*)calloc(number, byte-size)
realloc():-reallocates the memory occupied by malloc() or calloc() functions
ptr=realloc(ptr, new-size)
free():-frees the dynamically allocated memory
The syntax for free() function is given below:
free(ptr)
Program to for dynamic memory allocation

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int n,i,*ptr,sum=0;
    printf("Enter number of elements: ");
    scanf("%d",&n);
    ptr=(int*)malloc(n*sizeof(int));
    if(ptr==NULL)
    {
        printf("Sorry! unable to allocate memory");
        exit(0);
    }
    printf("Enter elements of array: ");
    for(i=0;i<n;++i)
    {
        scanf("%d",ptr+i);
        sum+=*(ptr+i);
    }
    printf("Sum=%d",sum);
    free(ptr);
    getch();
    return 0;
}
output:
Enter number of elements: 5
Enter elements of array: 1 2 3 4 5
Sum=15

4.List and explain different file opening modes
A file represents a sequence of bytes on the disk where a group of related data is stored.File is created for permanent storage of data. It is a ready-made structure.The fopen() function is used to create a new file or to open an existing file.
Different modes in file handling.

S.N Modes and Description
1 “r”: Opens a file for reading. The file must exists
2 “w”: Creates an empty file for writing. If a file with same name already exists, its content is erased and the file is considered as a new empty file.
3 “a”: Appends to a file. Writing operations append data at the end of file. The new file is created if it does not exist.
4 “r+”: Opens a file to update both reading and writing. The file must exist
5 “w+”: Creates an empty file for both reading and writing
6 “a+” :Opens a file for reading and appending

5.Write a function to check whether a given number is 987 or not

#include<conio.h>
#include<stdio.h>
int main()
{
      int n;
      printf("Enter any number\n");
      scanf("%d",&n);
      if(n==987)
      printf("The number is equal to 987\n");
      else
      printf("The number is not equal to 987\n");
      getch();
      return 0;
}




6. Write a function to copy content of one array to another array. You can consider any type of arrays.

#include<conio.h>
#include<stdio.h>
#include<string.h>
int main()
{
      int arr1[] = {2,7,5,6,3,4};
      int arr2[6];
      int i;
      printf("Content of first array\n");
      for(i=0;i<6;i++)
      printf("%d\t",arr1[i]);
      for(i=0;i<6;i++)
      {
        arr2[i]=arr1[i];
      }
      printf("\nContent of second array\n");
      for(i=0;i<6;i++)
      printf("%d\t",arr2[i]);
      getch();
      return 0;
}
Output:
Content of first array
2       7       5       6       3       4
Content of second array
2       7       5       6       3       4

Group “C”

7.List any five string handling functions. Write a program to swap contents of two string variables with each other.
The five string handling functions are:

  • strlen():- This function is used to find length of string
  • strcmp():-This function is used to compare two strings
  • strcpy():-This function is used to copy one string into another
  • strrev():- This function is used to reverse the content of string
  • strlwr():- This function is used to convert uppercase into lowercase
    #include<conio.h>
    #include<stdio.h>
    #include<string.h>
    int main()
    {
          char str1[20],str2[20],temp[20];
          printf("Enter first string\n");
          gets(str1);
          printf("Enter second string\n");
          gets(str2);
          strcpy(temp,str1);
          strcpy(str1,str2);
          strcpy(str2,temp);
          printf("The first string = %s\n",str1);
          printf("The second string = %s",str2);
          getch();
          return 0;
    }
    Output:
    Enter first string
    Kathmandu
    Enter second string
    Nepalganj
    The first string = Nepalganj
    The second string = Kathmandu

8.Write a program to print following pattern using for loop
2
4
8
14
22

#include<conio.h>
#include<stdio.h>
int main()
{
   int t,d,i;
   t=2;d=0;
   for(i=1;i<=5;i++)
   {
      t = t+d;
      d = d+2;
      printf("%d\n",t);
   }
      getch();
      return 0;
}
Output:
2
4
8
14
22

9. Write a program to store value of two integer variables in a file named “Two_Rupees.txt.

#include<stdio.h>
void main()
{
    FILE *fp;
    fp = fopen("Two_Ruppes.txt","w");
    int m,n;
    printf("Enter any two numbers: ");
    scanf("%d%d",n);
    if(fprintf(fp,"%d%d",m,n))
        printf("Successful");
    else
        printf("Unsuccessful");
    fclose(fp);
}
Output:
Enter any two numbers: 500 600
Successful

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