Why is does the file become NULL? - c

Question

I'm new on the subject of data structures so forgive me if Im asking a stupid question, I've been trying to figure this out myself but got nowhere.
These are the functions I'm working on and I think I initialized the file properly. However I couldn't understand why the function GetString prints an infinite loop of spaces. I have another function that exported some data on the said file. When i deleted the ImportListOfCompanyData function everything seems in order and the file is exported as it should be. However when ImportListOfCompanyData is there, the file is NULL.
void char * GetString(FILE *fp)
{
char c;
while(c != '\n')
{
c = fgetc(fp);
printf("%c", c);
}
}
void ImportListOfCompanyData(char *FileName, struct CompanyType s[], int maxit1, int maxit2)
{
FILE * fp;
char c;
fp = fopen(FileName, "r");
if (fp==NULL)
{
printf("Error creating the file \n");
exit(1);
}
GetString(fp);
fclose(fp);
}
Someone asked for the complete code: It's bit long sorry!
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAXNUM 100
struct Department
{
char DepName[MAXNUM];
int NuEmp;
double Budget;
int dflag;
};
typedef struct Department DEP;
struct CompanyType
{
char CompName[MAXNUM];
char OwnerName[MAXNUM];
int Year;
double StockPrice;
int flag;
DEP Dep[MAXNUM];
};
struct ImpDepartment
{
char IDepName[MAXNUM];
int INuEmp;
double IBudget;
int Idflag;
};
typedef struct ImpDepartment IDEP;
struct ImpCompanyType
{
char ICompName[MAXNUM];
char IOwnerName[MAXNUM];
int IYear;
double IStockPrice;
int Iflag;
IDEP IDep[MAXNUM];
};
void CreateCompany(struct CompanyType s[], char * cname, char * cowner, int year, double sprice, int i)
{
strcpy(s[i].CompName, cname);
strcpy(s[i].OwnerName, cowner);
s[i].Year = year;
s[i].StockPrice = sprice;
s[i].flag = 0;
}
int PrintCompany(struct CompanyType s[], int maxit1, int maxit2)
{
int flag = 0, i = 0;
while(i <= maxit1)
{
if(s[i].flag == 1)
{
flag = 1;
break;
}
printf("%d. Company %s: \n\n", i + 1, s[i].CompName);
printf("****************\n");
printf("Owned by: %s\n", s[i].OwnerName);
printf("Establishment year: %d\n", s[i].Year);
printf("Stock price: %.2lf\n", s[i].StockPrice);
printf("****************\n\n");
int j = 0;
while(j < maxit2)
{
if(s[i].Dep[j].dflag == 1)
{
flag = 1;
break;
}
printf("****************\n");
printf("%d. Department %s: \n", j + 1, s[i].Dep[j].DepName);
printf("Number of employees: %d\n", s[i].Dep[j].NuEmp);
printf("Budget: %.2lf\n", s[i].Dep[j].Budget);
printf("****************\n\n");
j++;
}
i++;
}
if(flag == 1)
return -1;
else
return 0;
}
int CompareName(char * str1, char * str2)
{
char *stra, *strb;
int result;
result = strcmp(str2, str1);
return result;
}
void DeleteCompany(struct CompanyType s[], char * cname, int n)
{
int i = 0, check = 0;
while(i <= n)
{
if(CompareName(s[i].CompName, cname)== 0)
{
check = 1;
break;
}
i++;
}
if(check == 1)
{
s[i].flag = 1;
printf("Company %s was successfully deleted!\n", s[i].CompName);
}
else
printf("The input is wrong!");
}
void UnDeleteCompany(struct CompanyType s[], char * cname, int n)
{
int i = 0, check = 0;
while(i <= n)
{
if(CompareName(s[i].CompName, cname)== 0)
{
check = 1;
break;
}
i++;
}
if(check == 1)
{
if(s[i].flag == 0)
{
printf("The Company %s wasn't deleted in the first place.\n\n", s[i].CompName);
}
else
{
s[i].flag = 0;
printf("Company %s was successfully undeleted!\n\n", s[i].CompName);
}
}
else
printf("The input is wrong!");
}
int SearchForCompany(struct CompanyType s[], char * cname, int maxit, int a)
{
int i = 0;
int check = 0;
int m = 0;
while(i <= maxit)
{
if(CompareName(s[i].CompName, cname)== 0)
{
check = 1;
break;
}
i++;
}
if(check == 1)
{
if(s[i].flag == 1)
{
printf("The company ""%s"" doesn't exist\n\n", cname);
}
else
{
if(a == 1)
{
printf("The company %s was found!", s[i].CompName, s[i].CompName);
m = 1;
}
else
m = 1;
}
}
else
printf("The company ""%s"" doesn't exist\n\n", cname);
if (m == 1)
return i;
else
return -1;
}
void AddDeparments(struct CompanyType s[], char * cname, int maxit, int a, char * dname, int nem, double bud, int depno)
{
int n;
n = SearchForCompany(s,cname, maxit, a);
if(maxit == -1)
return -1;
strcpy(s[n].Dep[depno].DepName, dname);
s[n].Dep[depno].NuEmp = nem;
s[n].Dep[depno].Budget = bud;
s[n].Dep[depno].dflag = 0;
printf("The department %s was created in the %s company\n",s[n].Dep[depno].DepName, s[n].CompName);
}
int SearchForDepartments(struct CompanyType s[], char * dname, int maxit1, int maxit2, int a, int *succ, int *i, int*j)
{
int check = 0;
while((*j) <= maxit1)
{
while((*i) <= maxit2)
{
if(CompareName(s[(*i)].Dep[(*j)].DepName, dname)== 0)
{
check = 1;
break;
}
(*i)++;
}
if(check == 1)
break;
(*j)++;
}
if(check == 1)
{
if(s[(*i)].Dep[(*j)].dflag == 1)
{
printf("The department ""%s"" doesn't exist.\n\n", dname);
}
else
(*succ) = 1;
}
else
printf("The department ""%s"" doesn't exist\n\n", dname);
if ((*succ) == 1)
return 0;
else
return -1;
}
int SearchForDelDepartments(struct CompanyType s[], char * dname, int maxit1, int maxit2, int a, int *succ, int *i, int*j)
{
int check = 0;
while((*j) <= maxit1)
{
while((*i) <= maxit2)
{
if(CompareName(s[(*i)].Dep[(*j)].DepName, dname)== 0)
{
check = 1;
break;
}
(*i)++;
}
if(check == 1)
break;
(*j)++;
}
if(check == 1)
{
if(s[(*i)].Dep[(*j)].dflag == 1)
{
(*succ) = 1;
}
}
else
printf("The department ""%s"" doesn't exist\n\n", dname);
if ((*succ) == 1)
return 0;
else
return -1;
}
void DeleteDepartments(struct CompanyType s[], int maxit1, int maxit2, int a, char * dname)
{
int n, i = 0, j = 0;
int succ = 0;
n = SearchForDepartments(s, dname, maxit1, maxit2, a, &succ, &i, &j);
if(n == -1)
return -1;
if(succ == 1)
{
s[i].Dep[j].dflag = 1;
printf("The department %s was deleted from the %s company\n", dname, s[i].CompName);
}
}
void UnDeleteDepartments(struct CompanyType s[], int maxit1, int maxit2, int a, char * dname)
{
int n, i = 0, j = 0;
int succ = 0;
n = SearchForDelDepartments(s, dname, maxit1, maxit2, a, &succ, &i, &j);
if(n == -1)
return -1;
if(succ == 1)
s[i].Dep[j].dflag = 0;
if(s[i].Dep[j].dflag == 0)
printf("The department %s was undeleted\n", dname);
}
ExportListOfCompanyData(struct CompanyType s[], int maxit1, int maxit2, char * FileName)
{
FILE *fp;
fp = fopen(FileName, "w");
if (fp==NULL)
{
printf("Error creating the file \n");
return -1;
}
int flag = 0, i = 0;
while(i <= maxit1)
{
if(s[i].flag == 1)
{
flag = 1;
break;
}
fprintf(fp,"%s\n", s[i].CompName);
fprintf(fp,"%s\n", s[i].OwnerName);
fprintf(fp,"%d\n", s[i].Year);
fprintf(fp,"%.2lf\n\n", s[i].StockPrice);
int j = 0;
while(j < maxit2)
{
if(s[i].Dep[j].dflag == 1)
{
flag = 1;
break;
}
fprintf(fp,"%s\n", s[i].Dep[j].DepName);
fprintf(fp,"%d\n", s[i].Dep[j].NuEmp);
fprintf(fp,"%.2lf\n\n", s[i].Dep[j].Budget);
j++;
}
i++;
}
if(flag == 1)
return -1;
else
return 0;
fclose(fp);
}
char * GetString(FILE *fp)
{
char * str; char c;
str = (char *)malloc(sizeof(char)* MAXNUM);
while(c != '\n')
{
c = fgetc(fp);
printf("%c", c);
}
}
ImportListOfCompanyData(char *FileName, struct CompanyType s[], int maxit1, int maxit2)
{
FILE * fp;
char c, *str;
str = (char *)malloc(sizeof(char)* MAXNUM);
fp = fopen(FileName, "r");
if (fp==NULL)
{
printf("Error creating the file \n");
exit(1);
}
int i = 0, j = 0, n;
GetString(fp);
fclose(fp);
return 0;
}
int main()
{
struct CompanyType CompanyList[MAXNUM];
CreateCompany(CompanyList, "alara inc", "alara", 2020, 6969, 0);
CreateCompany(CompanyList, "Shah inc", "shah", 2020, 3245, 1);
DeleteCompany(CompanyList, "Shah inc", 1);
SearchForCompany(CompanyList, "Shah inc", 1, 1);
UnDeleteCompany(CompanyList, "Shah inc", 1);
SearchForCompany(CompanyList, "Shah inc", 1, 1);
SearchForCompany(CompanyList, "alara inc", 1, 1);
AddDeparments(CompanyList, "alara inc", 1, 0, "computer", 20, 300, 0);
AddDeparments(CompanyList, "Shah inc", 1, 0, "chemistry", 30, 450, 0);
DeleteDepartments(CompanyList, 0, 1, 0, "chemistry");
UnDeleteDepartments(CompanyList, 0, 1, 0, "computer");
PrintCompany(CompanyList, 1, 1);
UnDeleteDepartments(CompanyList, 0, 1, 0, "chemistry");
ExportListOfCompanyData(CompanyList, 1, 1, "Data.txt");
ImportListOfCompanyData("Data.txt", CompanyList, 1, 1);
PrintCompany(CompanyList, 1, 1);
return 0;
}```

Answer 1

It was a really easy solution. I replaced "w" and "r" with "a+"
I guess it was a stupid question, still learning!