Practical C Programming

How to do it…

1. Open the file in read-only mode using the following code:

    fp = fopen (argv [1],"r");

2. If the file does not exist or does not have enough permissions, an error message will be displayed and the program will terminate, as shown in the following code:

if (fp == NULL) {    printf("%s file does not exist\n", argv[1]);    exit(1); }

3. Enter the word to be replaced using the following code:

printf("Enter a string to be replaced: ");scanf("%s", str1);

4. Enter the new word that will replace the old word using the following code:

printf("Enter the new string ");scanf("%s", str2);

5. Read a line from the file using the following code:

fgets(line, 255, fp);

6. Check whether the word to be replaced appears anywhere in the line using the following ...