trouble reading input

**panfilero** · 11-21-2005

I have this input file:

Code:

John LongLastName
143

Ann Iaeiouyhfsdf.
103

Ann X.
11

Jim C.
106

Ann B.
123

John LongLastName
143

class size 3

drop
11
103
106

I need to read this data in, and am trying to print it up on screen. At most the strings at the outputs shuld only have 9 characters... so John Longlastname... would be cut down to John Long for output.

I made this loop to read it in:

Code:

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

main(){

char temp_name[30];
char dummy[30];
int ID;

while( strstr("class siz",temp_name) == NULL) {

  fgets(temp_name,30,fin);        
       
        if(strlen(temp_name)>9){
        
           temp_name[9] = '\0' ; }

fscanf(fin," %d",&ID); 
                              
printf("%s\n",temp_name);
printf("%d\n",ID); 

}

but the output it gives me is:

Code:

John Long
143

143
Ann Iaeio
103

103
Ann X.

11

11
Jim C.

Could anyone tell me what I'm doing wrong? It looks like it's trying to scan in the blank line in the input.... I don't know how to get around this....

I've tried putting in a dummy fgets to take in the blank line but it didn't work

Thank You

**panfilero** · 11-21-2005

I've modified my loop a bit into this:

but it is still not working right, it is not stopping at class size like the while loop says and it is also printing blank lines... I don 't know why.

Code:

do {

  fgets(temp_name,30,fin);
  fgets(temp_num,30,fin);
  sscanf( temp_num, "%d", &ID );
  fgets( dummy,30,fin);
             
        if(strlen(temp_name)>9){
        
           temp_name[9] = '\0' ; }


    printf("%s\n",temp_name);
    printf("%d\n",ID); 


} while( strstr("class siz",temp_name) == NULL);

**mabuhay** · 11-21-2005

if you want just to show the content of your file on the screen, just use one fgets. If the nuber will never be longer than 9 chars, you can still use your check "if(strlen..." on each line you read.
If you want to enter a number if the number-line is read, you could check each line with isdigit, and when there are numbers, use the "sscanf(..."

if you don't want to show the blank line in the output, jump over the "printf(..." if in the readed string is just a '\n'
if(input_string[0] == '\n')

mfg

**dwks** · 11-21-2005

You're aware that fin is undeclared? (I assume it's FILE *fin.)

From that code there, it looks like you're trying to limit the user's input to 10 characters in length? Yes . . .

At most the strings at the outputs shuld only have 9 characters

fgets() will do that for you if you specify the size as 11 (9 + '\n' + NULL). Then you could discard the rest of the input:

Code:

#include <stdio.h>

int main(void) {
    int c;
    size_t len;
    char name[11];
    FILE *fin;

    if((fin = fopen("./thefile.ext", "rt")) == NULL) {
        fprintf(stderr, "\nCan't open file \"./thefile.ext\"\n");
        return 1;
    }

    while(fgets(name, sizeof(name), fin)) {
        len = strlen(name);
        if(name[len-1] != '\n') {
            while((c = getc(fin)) != '\n' && c != EOF);
        }

        name[len-1] = 0;

        /* Now you have a name in name which is < 10 chars long */
        /* Do whatever you want with it (I just print it) */
        puts(name);
    }

    fclose(fin);

    return 0;
}

I think that should work -- I don't have a compiler handy, though, so I can't tell you.

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