Program to search text in a file

Algorithm

Let's first see what should be the step-by-step procedure to compare two integers−

START
      
   Step 1 → Take two integer variables, say A & B
          
   Step 2 → Assign values to variables

   Step 3 → Compare variables if A is greater than B
   
   Step 4 → If true print A is greater than B
   
   Step 5 → If false print A is not greater than B

STOP

Flow Diagram

We can draw a flow diagram for this program as given below −

Pseudocode

Let's now see the pseudocode of this algorithm −

procedure compare(A, B)

   IF A is greater than B
      DISPLAY "A is greater than B"
   ELSE
      DISPLAY "A is not greater than B"
   END IF
      
end procedure

Implementation

Assuming we have file with name file_search.txt with this content −

Tutorials Point originated from the idea that there exists a class of readers who 
respond better to online content and prefer to learn new skills at their own pace 
from the comforts of their drawing rooms.

Now, we shall see the actual implementation of the program −

#include <stdio.h>
#include <string.h>
 
int main()
{
   FILE *fp;
   char word[50];
   char ch;
   char *filename = "somefile.txt";
   char *search = "to";
   int flag = 0;

   /*  open for writing */
   fp = fopen(filename, "r");
   
   do 
   {
      ch = fscanf(fp, "%s", word); 
      if(strcmp(word, search) == 0)
         flag = 1;     
   } while (ch != EOF); 

    if(flag)  
        printf("'%s' found in %s\n", search, filename);
    else
        printf("'%s' does not found in %s\n", search, filename);
        
   fclose(fp);
   return 0;
}

Output

Output of this program should be −

'to' appears 2 times in somefile.txt