Question

I am trying to read in a file, find the string “myprop” and after “myprop” will be an “=” sign then a number. I need to print out just that number as a string, getting rid of blank spaces and comments. I am able to locate the “myprop” string and then I believe I should be using fscanf but I am having trouble with that.

const char *get_filename_property()
{
    const char *filename  = "myfile.properties";
    const char *propkey = "myprop";
    char buffer[100], *buffPtr, lastChar, value[50];
    int line_num=1, i=0;

    FILE *fp;
    fp=fopen("myfile.properties", "r");
    if (fp == NULL)
        perror("Error opening file\n\n");

    while(fgets(buffer, 100, fp) != NULL)
    {
        if((strstr(buffer, propkey)) != NULL)
        {
            printf("Myprop found on line: %d\n", line_num);
            printf("\n%s\n", buffer);
        }
        line_num++;
    }
    if (fp)
        fclose(fp);
}  

int main(int argc, char *argv[])
{
    get_filename_property();
    system("pause");
    return(0);
}    

Answer 1

You can add sscanf in the moment when you find the mypop string in the file. Add the following line in your while loop:

sscanf(buf,"%*[^=]= %[^\n]",value);

"%*[^=]": This means that scanf capte all characters befor the = and ignore it

" %[^\n]": This means that you are capting all characters after the = till the end of your buffer string (even the space characters). only the space characters in the beggining of the value string will not capted

add it in this way

while(fgets(buffer, 100, fp) != NULL)
 {
  if((strstr(buffer, propkey)) != NULL)
  {
   printf("Myprop found on line: %d\n", line_num);
   printf("\n%s\n", buffer);
   sscanf(buf,"%*[^=]= %[^\n]",value);
   printf("\nvalue is %s\n", value);
   break;
  }
  line_num++;
 }