How to replace a word in a file.

[madhumathikv]

This is the code i have written to replace a line which contains GATEWAY.

#include<stdlib.h>
#include <string.h>
#define IF_CONF "ifffcccccc.txt"
main()
{
        char line[130],line1[130];
 
        FILE *fp=NULL,*ofp=NULL;
        fp=fopen(IF_CONF,"rw+");
        ofp=fopen(IF_CONF,"rw+");
        if(fp==NULL)
        {
                printf("\n\nerror\n");
                return -1;
        }
        while (fgets(line,sizeof(line),fp))
        {
 
                printf("Line Read: %s\n",line);
                if(strstr(line, "GATEWAY") != NULL)
                {
                        fclose(fp);
                        printf("Replacing\n");
                        strcpy(line,"GATEWAY=");
                        strcat(line,"111.111.111.111\n");
                        printf("%s",line);
                fseek(ofp,0,SEEK_CUR);
                fputs(line,ofp);
                printf("\nReplace Over\n");
                break;
 
                }
 
 
                }
 
                fgets(line1,sizeof(line1),ofp);
        }
 
printf("The line = %s\n\n\n",line);
        fclose(ofp);
return 0;
}
 

The problem it is deleting the next line charecters.


The file "ifffcccccc.txt" contains
AAAAAAAAAAAAAAAAA
BBBBBBBBBBBBBBBB
DDDDDDDDDDDDDD
GATEWAY=191.1.51.21
HELLO
HKKKKKKK



Please any one help..

[sicarie]

You got this to compile? What compiler/version? I can't even get it to compile with cygwin gcc v 3.4.4

[xoinki]

hi,
u cant modify contents of a file once it is open.. wat u can do it rewrite the whole content once again.. and fclose the file.

Regards
Xoinki

[madhumathikv]

You got this to compile? What compiler/version? I can't even get it to compile with cygwin gcc v 3.4.4

ya i am able to complile it..

[madhumathikv]

hi,
u cant modify contents of a file once it is open.. wat u can do it rewrite the whole content once again.. and fclose the file.

Regards
Xoinki

I am able to modify it , but the problem is , i am not able to write to a line more than the string length of the original contents of the line.if i write like that the next line contents is overwritten.

[sicarie]

I am able to modify it , but the problem is , i am not able to write to a line more than the string length of the original contents of the line.if i write like that the next line contents is overwritten.

Right, well, apparently you're not going to share your compiler or version, so why not read the entire file in, close it (still holding the file contents in memory), and then open a new file output stream and write the data you need?