I'm trying to write a simple program that will read a file with 3 columns of data, test the last column against a given value, and print out the current line if the test is true. This is my input file (Table1b.txt): -1.84 13.16 TO -1.99 13.36 RRV -2.20 14.65 TO -1.19 14.41 G -2.44 13.34 G And this is my program: #include     main()  {       FILE *fptr_in,*fptr_out;       int i=0;       char type[4];       float met,vel;         fptr_in = fopen("Table1b.txt","r");       fptr_out =  fopen("Table1c.txt","w");         while(i4)       {            fscanf(fptr_in,"%f %f  %s",&met,&vel,&type);            if (type=="RRV")            fprintf(fptr_out,"%f %f  %s",met,vel,type);            i++;       }         fclose(fptr_in);       fclose(fptr_out);  }  But for some reason I can never get the if statement to read true. The program loops and prints perfectly otherwise - what am I doing wrong??

Hi, I think your bug lies in the fact that you are trying to equate two strings. if i declare something like char type[4]; later when i refer to type i am refering to the address of the first letter of the string. So in effect when you compare two strings using a = sign you are comparing addresses. To compare two strings you probably want to use this function. strcmp(string1,string2) Include the header This function returns 0 if the two are equal a value 0 if otherwise. Why dont you give that a try. zzray

I'm sorry jennifer, This posting thing is driving me nuts coz it leaves out half my message. Ignore the prev message from Include the header. Include string.h . The function returns 0 if both are equal some value less than zero if string1 comes before string2 in the dictionary and a value greater than zero if otherwise. This is what i meant to say but it seems to chop up my posts. zzray

Ah ha! It works perfectly now - thanks!