USE OF CALLOC

#include<stdio.h>
#include<stdlib.h>
int main()
{
 int num,i,*ptr,sum=0;
 printf("enter number of elements:");
 scanf("%d",&num);
 ptr=(int*)calloc(num,sizeof(int));//only //difference is on the syntax there is comma //in caaloc and                                                                                  //*(star)in malloc
 if(ptr==NULL)
 {
  printf("error !memory not allocated ");
  exit(0);
 }
 printf("enter element of array:");
 for(i=0;i<num;i++)
 {
  scanf("%d",ptr+i);
  sum=sum+(*(ptr+i));
 
 }
 printf("SUM=%d",sum);
 free(ptr);
 return 0;
}

USE OF MALLOC

#include<stdio.h>
#include<stdlib.h>
int main()
{
 int num,i,*ptr,sum=0;
 printf("enter number of elements:");
 scanf("%d",&num);
 ptr=(int*)malloc(num*sizeof(int));
 if(ptr==NULL)
 {
  printf("error !memory not allocated ");
  exit(0);
 }
 printf("enter element of array:");
 for(i=0;i<num;i++)
 {
  scanf("%d",ptr+i);
  sum=sum+(*(ptr+i));
 
 }
 printf("SUM=%d",sum);
 free(ptr);
 return 0;
}

binary search in a array

#include<stdio.h>
int main()
{
int a[10];
int i,k,mid,l=0,u=8,item;
for(i=0;i<10;i++)
{
scanf("%d",&a[i]);
}
mid=(0+9)/2;
printf("enter the number to search: ");
scanf("%d",&item);
while(l<=u)
{
if(item==a[mid])
{

printf("%d", mid+1);
break;
  }
else if(item<a[mid])
u=mid-1;
else
l=mid+1;


}
}

file handling read and write in text

#include<stdio.h>
#include<conio.h>
int main()
{
FILE *f;
char c;
f=fopen("data.txt","w");
while(c!='.') //it will terminate the loop when u enter the full stop(.)
            
{
c=getche();
fputc(c,f);

}
fclose(f);
printf("\ncontent of field are :");
f=fopen("data.txt","r");
while(!feof(f))
{
printf("%c",fgetc(f));
}
}
                            OUTPUT