C Programming Examples Tutorial Index

C File I/O Programs

Number of lines in a file can be determined by counting the number of new line characters present.



#include <stdio.h>

int main()
/* Ask for a filename and count number of lines in the file*/
{
    //a pointer to a FILE structure
    FILE *fp;
    int no_lines = 0;
    //consider 40 character string to store filename
    char filename[40], sample_chr;
    //asks user for file name
    printf("Enter file name: ");
    //receives file name from user and stores in a string named 'filename'
    scanf("%s", filename);
    //open file in read mode
    fp = fopen(filename, "r");
    //get character from file and store in sample_chr
    sample_chr = getc(fp);
    while (sample_chr != EOF) {
        //Count whenever sample_chr is blank (new line) is encountered
        if (sample_chr == '')
        {    
            //increment variable 'no_lines' by 1
            no_lines=no_lines+1;
        }
        //take next character from file.
        sample_chr = getc(fp);
    }
    fclose(fp); //close file.
    printf("There are %d lines in %s 
    ", no_lines, filename);
    return 0;
}

Program Output:

Enter file name:abc.txt

There are 4 lines in abc.txt

Explanation:

In this program, name of the file to be read is taken as input. A file by the given name is opened in read-mode using a File pointer 'fp'. Characters from the file are read into a char variable 'sample_chr' with the help of getc function. If a new line character(' ') is encountered, the integer variable 'no_lines' is incremented. If the character read into 'sample_char' is not a new line character, next character is read from the file. This process is continued until the last character of the file(EOF) is encountered. The file pointer is then closed and the total number of lines is shown as output.



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