Question

A. File I/O using C library functions File I/O in C is achieved using a file pointer to access or modify files. Processing files in C is a four-step process: o Declare a file pointer. o Open the desired file using the pointer. o Read from or write to the file and finally, o Close the file. FILE is a structure defined in <stdio.h>. Files can be opened using the fopen() function. This function takes two arguments, the filename and the permission that should be attributed to the file while opening. It returns a pointer to the file is it is opened successfully. For example, FILE *ptr; ptr = fopen ("example.txt", "r"); opens a file called example.txt with the read permission only. That means that the content of example.txt can only be read and no data may be written to it. Files can be closed using the fclose() function. It takes a file pointer as an argument. Always make sure files are closed if no additional operations will be performed on a file that is open. For example, fclose (ptr);

Answer 1

C Program:

/* C Program that counts number of words and lines */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

int main()
{
FILE *fp;
char fileName[50];
char input;
int lines=0, words=0, chars=0;

//Reading file name
printf("Enter file name: ");
scanf("%s", fileName);

//Opening file
fp = fopen(fileName, "r");

//Checking status
if(fp==NULL)
{
printf("Unable to open file\n");
exit(EXIT_FAILURE);
}

//Reading input from file
while( (input = getc(fp)) != EOF )
{
//Spaces and tab
if(!isspace(input))
{
//Updating chars
chars++;
}
//New line character
if(input=='\n')
{
//Incrementing number of lines
lines++;
}
//Words
if(input=='\n' || input==' ' || input=='\t')
{
//Incrementing number of words
words++;
}
}
printf("\nNumber of Lines: %d", lines);
printf("\nNumber of Words: %d", words);
printf("\nNumber of Characters: %d\n", chars);

//Closing file
fclose(fp);
return 0;
}

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Sample Run:

C:\TC\wordLineCharCount\bin\Debug\wordLineCharCount.exe Enter file name: data.txt Number of Lines: 8 Number of wor ds: 52 Number of characters: 213 Process returned 0 (0x0) Press any key to continue. execution time : 4.108 s