Edit .csv files in C

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Edit .csv files in C

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I need to make a programming code in C, in which I ask the user for the name of a city, present in the first file (cities.csv), and I have to remove the id from the inserted city. Then, this id must match another id, present in a second file (meteorologia.csv), and then edit the meteorological information, present in the second file. I've been doing a lot of research and with some help, I got the code below. However, when compiled, everything in the second file is replaced by the data in the first file. Could someone help me?

#define TAM_STR 100

typedef struct city_t{
char city_id[TAM_STR];
char city_name[TAM_STR];
char county_name[TAM_STR];
char district_name[TAM_STR]; } city_t;

typedef struct meteo_t{
char meteo_id[TAM_STR];
char meteo_city_id[TAM_STR];
char tempt_max[TAM_STR];
char tempt_min[TAM_STR];
char humidity[TAM_STR];
char preassure[TAM_STR];
char date[11]; } meteo_t;

int editInfo(){
char city[100];    

struct city_t INFO;
struct meteo_t DATA;

printf("Qual e a cidade: ");
scanf("%[^\n]%*c", city);

FILE* stream = fopen("cidades.csv", "r");
FILE* meteo =fopen ("meteorologia.csv","w");

if("cidades.csv" == NULL || "meteorologia.csv" == NULL)
{
    printf("Nao e possivel abrir o ficheiro\n");
    return -1;
}

char line[1024];
while (fgets(line, 1024, stream) != NULL)
{
    sscanf(line, "%s", INFO.city_name);
    if(strcmp(city, INFO.city_name) == 0)
    { //pelo que me disseram, falta aqui um while
        sscanf(line, "%s,%s,%s,%s,%s", DATA.tempt_max, DATA.tempt_min, DATA.humidity, DATA.preassure, DATA.date);
        printf("Introduza o valor da temperatura maxima: ");
                scanf("%s", DATA.tempt_max);
                printf("Introduza o valor da temperatura minima: ");
                scanf("%s", DATA.tempt_min);
                printf("Introduza o valor da humidade: ");
                scanf("%s", DATA.humidity);
                printf("Introduza o valor da pressao: ");
                scanf("%s", DATA.preassure);
                printf("Introduza a data correspondente, no formato AAAA-MM-DD: ");
                scanf("%s", DATA.date);

                fprintf(meteo, "%s,%s,%s,%s,%s", DATA.tempt_max, DATA.tempt_min, DATA.humidity, DATA.preassure, DATA.date);
                printf("Informacao alterada com sucesso!");

                fclose(stream);
                fclose(meteo);
    }
    else
    {
        fputs(line, meteo);
    }
}           
}

The cities.csv file has 152 rows and 4 columns in this format:

id_cidade,cidade,concelho,distrito

such as:

98,Porto,Porto,Porto

The weather file has 152 rows and 7 columns in this format:

id_meteo,id_cidade,temp_max,tem_min,humidade,pressao,data

such as:

98,98,9.5,0.3,62,1025,2018-02-12

Any help is welcome. Thank you!

c csv

asked by anonymous 15.02.2018 / 18:44

1 answer

Matrix multiplication does not work kivy in python 3.6

score 0 · Answer 1

There were several errors. There was an error in sscanf that caused the input received by reading the cities.csv file to be the city code instead of the name. After that there was an if that compared the input written by the user with the name of the city with the input of the file, in the case the code of the city. The else would have to copy the line from the cities.csv file to meteorology.csv
And a few more bugs to follow the corrected and functional code
I forgot to mention the error in your city.csv file for some reason when entering information without commas, for example "98, Port, Port, Port" gives an error in SCANF
The right thing would be to enter the information with spaces after the commas, for example, "98, Porto, Porto, Porto"
I hope agor works

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

#define TAM_STR 100

typedef struct city_t{
char city_id[TAM_STR];
char city_name[TAM_STR];
char county_name[TAM_STR];
char district_name[TAM_STR]; } city_t;

typedef struct meteo_t{
char meteo_id[TAM_STR];
char meteo_city_id[TAM_STR];
char tempt_max[TAM_STR];
char tempt_min[TAM_STR];
char humidity[TAM_STR];
char preassure[TAM_STR];
char date[11]; } meteo_t;

int editInfo(){
char city[100];    

struct city_t INFO;
struct meteo_t DATA;

printf("Qual e a cidade: ");
scanf("%[^\n]%*c", city);

FILE* stream = fopen("cidades.csv", "r");
FILE* meteo = fopen("meteorologia.csv","w");

if("cidades.csv" == NULL || "meteorologia.csv" == NULL)
{
    printf("Nao e possivel abrir o ficheiro\n");
    return -1;
}

char line[1024];
while (fgets(line, 1024, stream) != NULL)
{
    sscanf(line, "%s%s", INFO.city_id, INFO.city_name);

    char *pointerComma = NULL;
    char *pointerCityName = NULL;
    pointerComma = strchr(INFO.city_name, ',');
    pointerCityName = INFO.city_name;

    int indexComma = pointerComma - pointerCityName;
    INFO.city_name[indexComma] = 0;

    if(strcmp(city, INFO.city_name) == 0)
    { //pelo que me disseram, falta aqui um while
        sscanf(line, "%s %s %s %s %s", DATA.tempt_max, DATA.tempt_min, DATA.humidity, DATA.preassure, DATA.date);
        printf("Introduza o valor da temperatura maxima: ");
        scanf("%s", DATA.tempt_max);
        printf("Introduza o valor da temperatura minima: ");
        scanf("%s", DATA.tempt_min);
        printf("Introduza o valor da humidade: ");
        scanf("%s", DATA.humidity);
        printf("Introduza o valor da pressao: ");
        scanf("%s", DATA.preassure);
        printf("Introduza a data correspondente, no formato AAAA-MM-DD: ");
        scanf("%s", DATA.date);

        fprintf(meteo, "%s,%s,%s,%s,%s", DATA.tempt_max, DATA.tempt_min, DATA.humidity, DATA.preassure, DATA.date);
        printf("Informacao alterada com sucesso!");

        fclose(stream);
        fclose(meteo);
    }
}

return 0;        
}


int main() {

editInfo();
return 0;
}