File handling functions in C

Function	Syntax	Example
fopen - Open file	FILE * fopen(char * filename, char * mode) Filename – string filename with path Mode – mode of opening              r    read only             w   write only             a    append file                +    read and write (r+/w+/a+)             b   binary file Return value – FILE pointer on success                          NULL on failure	FILE * infile ; Infile = fopen(“a.txt”,”r”); FILE *outfile = fopen(“b.txt”,”w”); if(infile==NULL || outfile==NULL) { printf(“error”); }
fclose – close the open file.  Note that when a program ends all open files are closed automatically	fclose(FILE *fptr) fptr – FILE * of the open file Returns void	fclose(infile);
fgetc – read one char from file	int fgetc(FILE *fptr) fptr – FILE * of the open file returns – character read             -1 on eof or error	while( (ch=fgetc())!=-1)       putchar(ch); //display content of file //on screen
fputc – write one character to the file	int fputc(int ch,FILE *fptr) ch – character to write fptr – open file pointer returns character written            EOF if there is error	for(ch=’A’;ch<=’Z’;ch++)        fputc(ch,fptr);
fscanf – Formatted read from file	int fscanf(FILE *ptr,char * fmt,…) ptr – FILE pointer fmt – format specifier for variables to be read Returns – number of values read successfully	fscanf(infile, “%d %d”,&n1,&n2);
fprintf – formatted write to file	int fprintf(FILE *ptr,char * fmt,…) ptr – FILE pointer fmt – format specifier for variables to be  read Returns – number of characters  printed or negative number on error	fprintf(outfile,“Value is %d\n”,n1);
fread – read blocks from binary file	int fread( void *buffer, size_t size, size_t num, FILE *ptr ) buffer – stores the pointer to value read size – size of the buffer num – number of blocks to be read ptr – file pointer Returns – number of values read	Char *str = malloc(50); fread(str,50,1,infile);
fwrite – write blocks to a binary file	int fwrite( void *buffer, size_t size, size_t num, FILE *ptr ) buffer – address of value to write size – size of the buffer num – number of blocks to be read ptr – file pointer Returns – number of values written	for(i=0;i<10;i++)    fwrite(&i,sizeof(i),1,outfile); char a[]=”end”; fwrite(a,strlen(a)+1,1,outfile);
fseek – move the file pointer by given offset	int fseek(FILE*ptr,long offset,int whence) ptr – file pointer offset – offset in bytes from third parameter whence – SEEK_SET – from beginning of file SEEK_CUR – from current position SEEK_END – from end of file Returns – zero on success Non-zero on failure	if(fseek(infile,4L,SEEK_SET)==0) {      char ch=fgetc(infile);      printf(“The fourth char of the file is %c\n”,ch);  }
ftell – get the position of file pointer	int ftell(FILE *ptr) ptr – FILE pointer Returns – position of file pointer -1 on error	FILE *ptr = fopen(b[1],"r"); fseek(ptr,0L,SEEK_END);  int size_of_file = ftell(ptr);
rewind – moves the file pointer to the beginning of the file	void rewind(FILE *ptr) ptr – FILE pointer	rewind(infile); int n = fscanf(infile,”%d”,&n);