reading string from a file in c

Question

I've got an input file like this:

1 2 2 Medium 
1 2 0 Medium
2 1 0 Medium
2 0 2 Medium

I am using fscanf() to read in the integer values and that is working fine. does anyone have any ideas how to read in the string and place it in a string variable???

int x,y,z; 
char* cs; 
fscanf(fp3,"%d",&x); 
fscanf(fp3,"%d",&y); 
fscanf(fp3,"%d",&z); 
fscanf(fp3,"%s",&cs);

Answer 1

You need already allocated space to store the string. Try something like this:

int x,y,z; 
char cs[20];
fscanf(fp3,"%d",&x); 
fscanf(fp3,"%d",&y); 
fscanf(fp3,"%d",&z); 
fscanf(fp3,"%19s",cs);

You can also scan for all the values at once:

fscanf(fp3,"%d %d %d %19s", &x, &y, &z, cs);

N.B: Always use %<length>s in a scanf pattern to prevent buffer overflow.

Answer 2

Watch out for two things:

• You need to reserve a buffer to copy the string into.
• Also never ever use a plain "%s" scanf pattern. It should be forbidden. Instead insert the length of the buffer, minus 1 between the % and the s. E.g., "%7s" for an 8 byte buffer.

Answer 3

2 things to say:

1. It looks nicer when you use one format string
2. You should use a loop

Here's some code:

int a,b,c;
char str[256];
while(fscanf(fd, "%d %d %d %s ", &a, &b, &c, str) == 4){
    //get some coffee
}

this is a standard while not End of File loop. Also, str doesn't need & because it already is a pointer and doesn't need to be referenced like a, b or c. The space at the end of the format string, after %s, means it will stop once that one space is read. This way it is not included in the string str.