how to detect a particular string in a file using C program

Question

I have a file and I want to read this file using C program using file operations. Then i want to take parameters from that file. Lets say nalu_type=x. So whenever i detect the string nalu_type in that file I want to put the value x in an array which is defined by me. please tell me how to do it.

Thanks in Advance Sanket

Rahul Yadav · Accepted Answer · 2012-10-08 15:31:47Z

5

# include<stdio.h>
# include <conio.h>
# include <string.h>

void main()
{
    int noc=0,l;
    FILE *fp;
    char *str2,ch;
    char*str1;
    clrscr();
   printf("Enter the String to be matched\n");
    gets(str1);
    l=strlen(str1);
    fp=fopen("A.C","r");
    while(1)
       {
        ch=fgetc(fp);
        if(ch==EOF)
        break;
        else if(ch==' ')
         {
          fgets(str2,l+1,fp);
           if((strcmp(str1,str2))==NULL)
            noc++;
         }
        }

      printf("NO of occurence is: %d",noc);
      getch();
}

edited Oct 8, 2012 at 15:31

answered Oct 8, 2012 at 15:14

Rahul Yadav

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1 Comment

Shakti Prakash Singh Over a year ago

Are you checking for the occurence of the given string in the first string inside the file? I guess that is being skipped.

sunmoon · Accepted Answer · 2011-03-14 06:14:41Z

2

If the format is nalu_type = x

 fscanf(fp, "%s", buf);
if !strcmp(buf, "nalu_type")
{
   fscanf(fp, "%s", buf);
    if ( ! strcmp(buf, "="))
     fscanf(fp, "%s", buf);
    else
    printf("\n Not a valid format");
}

Repeat the above if until end of file.

answered Mar 14, 2011 at 6:14

sunmoon

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2 Comments

Nimit Over a year ago

I am getting segmentation fault. Can you please describe your answer in detail?

jww Over a year ago

@sunmoon - you added spaces around the = sign. The original question did not have them. strstr may be a better choice without spaces.

nycdan · Accepted Answer · 2011-03-14 06:13:47Z

0

This sounds a bit like homework but here's a basic strategy that should help.

You basically just want to parse the file as text. Iteratively find the index of string "nalu_type=" and then get a substring of what comes after that. The part you are missing is what delimits the value x. You would need to know what the end-delimiter is at least.

answered Mar 14, 2011 at 6:13

nycdan

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