Fwrite Function : Write Block of Memory to Binary Mode File

fwrite :

1. This Function is Used in Binary Mode.
2. Function Writes Block of Data to Binary Mode File.[i.e Writes Block to Binary File]

Syntax :

int fwrite(void *Buffer,int Size,int Count,FILE *ptr);
Parameters :
“Buffer” is Variable of Pointer Type.
“Buffer” Holds Starting Address of the Block to be Written on File.
Size Specifies the Size in Bytes of Individual Data Item.
Count Specifies “Number of Items to Be Written Onto File“.
Examples :
1. To Write Variable x of type Float to File
float x;
FILE *fptr;
int fwrite(&x,sizeof(x),1,fptr);
2 . Write Array of 100 Elements
float x[100];
FILE *fptr;
int fwrite(&x,sizeof(x),100,fptr);
100 Specifies That Write 100 Floating Values to File Starting From Address Specified in Variable ‘x’.
3. Write Structure to File
struct student
{
   char name[50];
   int roll;
};
main()
{
FILE *fptr;
struct student st[20];
int num;
if((fptr = fopen("ip.txt","wb+"))==NULL)
  {
  printf("nError in Opening File");
  exit(0);
  } 
printf("How many Students : ");
scanf("%d",&num);

for(i=0;i<num;i++)
  {
  printf("nEnter the Name and Roll Number");
  scnaf("%s %d",st.name,&st.roll);
  fwrite(&st,sizeof(st),1,fptr);
  }
//Structure is Written on File
getch();
}