Function casts itself c, after it has been casted twice - c

Question

I've got a university project where I have to write a database of workers. I decided to use dynamic array of structures:
struct data
{
char id[50];
char name[50];
char surname[50];
char account_num[50];
double net_pension,taxed_pension;
};
int main()
{
int current_size=0;
struct data *database;//creating a table
database=(struct data*)malloc(1*sizeof(struct data));//memory allocation
menu(database);//running menu
return 0;
}
function menu
void menu(struct data *database)
{
int current_size=1;
int input=0;
char inpt[512];
do
{
printf("Input function or input help for list of avaible commands \n");
fgets(inpt,511,stdin);
input=mod_input(inpt);
if(input==404)
{
printf("Function does not exist \n");
}
else if(input==1)
{
print_result(database,current_size);
}
else if(input==2)
{
add_element(database,&current_size);
}
else if(input==3)
{
modify_element(database,current_size);
}
else if(input==4)
{
sort_table(database, current_size);
}
else if(input==5)
{
search(database,current_size);
}
else if(input==6)
{
hilfe();
}
else if(input==7)
{
search_by_col(database,current_size);
}
input=8;
}
while(input!=0);
}
decides what we want to do, for example writing "add" will start my problematic function, which is supposed to add new records
void add_element(struct data *database,int *size)
{
int subflag=0;
char inpt[50];
int place=((*size)-1);
int pass=(*size);
printf("%i",pass);
if((*size)!=1)
{
modify_element(database,(*size));
}
do
{
printf("Input unical ID \n");
fgets(inpt,50,stdin);
if(does_exist(inpt,database,pass)==1)
{
subflag=1;
strncpy(database[place].id,inpt,50);
}
else
{
printf("ID exists");
}
}
while(subflag==0);
subflag=0;
do
{
printf("Input name \n");
fgets(inpt,50,stdin);
if(is_word(inpt)==1)
{
subflag=1;
strcpy(database[place].name,inpt);
}
}
while(subflag==0);
subflag=0;
do
{
printf("Input surname \n");
fgets(inpt,50,stdin);
if(is_word(inpt)==1)
{
subflag=1;
strcpy(database[place].surname,inpt);
}
}
while(subflag==0);
subflag=0;
do
{
printf("Input account number \n");
fgets(inpt,50,stdin);
if(is_accnum(inpt)==1)
{
subflag=1;
strcpy(database[place].account_num,inpt);
}
}
while(subflag==0);
subflag=0;
do
{
printf("Input net gain \n");
fgets(inpt,50,stdin);
if(is_num(inpt)==true)
{
printf("%d",atof(inpt));
subflag=1;
database[place].net_pension=atof(inpt);
}
}
while(subflag==0);
subflag=0;
do
{
printf("Input taxed gain \n");
fgets(inpt,50,stdin);
if(is_num(inpt)==true)
{
subflag=1;
database[place].taxed_pension=atof(inpt);
}
}
while(subflag==0);
printf("record added \n");
if((*size)==1)
(*size)++;
}
function modify_size reallocs memory, does_exist ensures, that id's are unique, is acc_num, num and word checks input for given rules. They all work perfectly when you use function first time. But after you try to add second one "record added" does not display and function add runs from the beginning. I ahve no idea why. That is the main problem. Secondary one is menu, because when you input "print" it runs add_element. Code that converts input is:
int mod_input(char function[])
{
printf(function);
if(strcmp(function,"modify")==1)
return 3;
else if(strcmp(function,"sort")==1)
return 4;
else if(strcmp(function,"search")==1)
return 5;
else if(strcmp(function,"help")==1)
return 6;
else if(strcmp(function,"add")==1)
return 2;
else if(strcmp(function,"print")==1)
return 1;
else if(strcmp(function,"search_by_column")==1)
return 7;
return 404;
}
Thank you in advance for help. Also I know that some parts could be done better, but for now, I try to just force it to work.
whole programme
lab3.c and header

Answer 1

Intuitively, what you need to do is pass around a pointer to a pointer to your array, not just a pointer to it. And that's what BLUEPIXY was trying to get at in a comment.
The problem is that if you do x = realloc(y, new_size), there's no guarantee that x will be equal to y.
In particular, database = realloc(database, new_size) inside a subroutine may leave the subroutine with a different value for database than the one passed in as an argument. The caller still has the old value for database.
The results are undefined, and may include worse than what you got.
What you want is something like
struct data *datap;
struct data **database = &datap;
*database = malloc(sizeof(struct data))
With corresponding changes all the way down - basically pass database, and set *database = realloc(...) when you get to that stage.
Also, make sure you update *size appropriately at the same time.