处理数据-C编程

Question

Ive written this code, to read data from a sensor:

char c;
do{
    while(!read(fd, &c, 1));    
} while (c!='$');   

do{
    while(!read(fd, &c, 1));    
} while (c!=',');   

do{
    while(!read(fd, &c, 1));

    printf("%c",c); 
    fp = fopen("/var/www/Sensor_data.txt", "a");
    fprintf(fp, "%c%", c);
    fclose(fp); 

} while (c!='\n');

The file then looks like

518.088131, 0.272969,0.376242,0.522998,0.368944,0.347478,0.343025,0.252323 ,0.612587,0.552753,0.120302,806.230415

I would then like a way to procces this data, so I take data number 2,3,4,5,6,7,8 (the ones in bold) and transfer to new files one for each. Anyone can give an example of a program doing this? or preferred to modify my program so it makes a file with all data, and 7 other files with 1 data in each.

Answer 1

Something like this will do the trick. Not very scalable though :S

// This part has to go before main function starts
char int_to_char(int n){
    return (char) n + (int)'0';
}

// and this replaces what you already had
int reading = 1;
do{
    while(!read(fd, &c, 1));          // <- you should change this

    printf("%c",c); 
    fp = fopen("/var/www/Sensor_data.txt", "a");
    fprintf(fp, "%c", c);
    fclose(fp); 

    if (c == ',')
        reading++ ;

    else{        
        if (reading >= 2 && reading <= 8){              // 2nd to 8th reading
            char temp[] = "/var/www/Sensor_data .txt";  // <- Added a space, which I'm 
                                                    //  gonna substitute with a number
            temp[20] = int_to_char(reading);            // Substitute the space
            fp = fopen(temp, "a");
            fprintf(fp, "%c", c);
            fclose(fp);
        }
    }

} while (c!='\n');

The conversion from int to char only works if the number is between 0 and 9.

Answer 2

With this code:

FILE *fp;   
    char c;
    do{
        while(!read(fd, &c, 1));    
    }while (c!='$');    

    char int_to_char(int n){
    return (char) n + (int)'0';
}

int reading = 1;
do{
    while(!read(fd, &c, 1));          // <- you should change this

    printf("%c",c); 
    fp = fopen("/var/www/Sensor_data.txt", "a");
    fprintf(fp, "%c", c);
    fclose(fp); 

    if (c == ',')
        reading++ ;

    else{        
        if (reading >= 2 && reading <= 8){              // 2nd to 8th reading
            char temp[] = "/var/www/Sensor_data .txt";  // <- Added a space, which I'm 
                                                    //  gonna substitute with a number
            temp[20] = int_to_char(reading);            // Substitute the space
            fp = fopen(temp, "a");
            fprintf(fp, "%c", c);
            fclose(fp);
        }
    }

} while (c!='\n');

I get 523.488072, 0.326624,0.471786,0.472091,0.317701,0.430966,0.292683,0.260292 ,0.653686,0.608487,0.116710,806.211857 in the Sensor_data.txt file. In the other 7 files i get 2 3 . 4 8 8 0. 1 value in each file. What i intend is to get the 7 value marked with bold into 7 separate files. I dont know if this was clear and if its whats happening for you SlySherZ?

Just read that the conversion between int to char only works if the number it between 0-9 could this be the problem?