Linker error in turboc++: undefined symbol - linker

Question

I am trying the following program on TurboC. I am getting a linker error for one of the function prototypes.
The error is: undefined symbol checkbranch(char near*) in module student.cpp where student.cpp is the name of the file.
The code compiles with no errors and I am not able to detect the error here. Any help would be appreciated.
#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#include<iomanip.h>
#include<fstream.h>
#include<string.h>
#include<ctype.h>
void checkbranch(char string[]);
void checkusn(char string[]);
void checksem(char string[]);
void checkname(char string[]);
fstream file;
class iobuffer
{
public: char maxbyte[120];
iobuffer();
};
iobuffer::iobuffer()
{
for(int i=0; i<120; i++)
maxbyte[i]='\0';
}
class student
{
public: char usn[20], name[25], sem[10], address[20], branch[10];
student()
{
strcpy(name,"");
strcpy(usn, "");
strcpy(sem, "");
strcpy(branch, "");
strcpy(address, "");
}
void read();
void display();
void rsem();
void rname();
void rusn();
void rbranch();
void raddress();
};
void student::rusn()
{
cout<<"\n\tEnter the new usn: ";
gets(usn);
checkusn(usn);
}
void student::rname()
{
cout<<"\n\tEnter the name: ";
gets(name);
checkname(name);
}
void student::rsem()
{
cout<<"\n\tEnter the sem: ";
gets(sem);
checksem(sem);
}
void checkbranch(char string[]);
void student::rbranch()
{
cout<<"\n\tEnter the branch: ";
gets(branch);
checkbranch(branch);
}
void student::raddress()
{
cout<<"\n\tEnter the address: ";
gets(address);
}
void checkname(char arr[])
{
for(int j=0; arr[j]!='\0'; j++)
if((!isalpha(arr[j]))&&(arr[j]!=' '))
{
cout<<"\n\tWrong input. Re-enter: ";
gets(arr);
j=-1;
}
}
void student::read()
{
cout<<"\n\tUSN: ";
gets(usn);
checkusn(usn);
cout<<"\n\tName: ";
gets(name);
checkname(name);
cout<<"\n\tSem: ";
gets(sem);
checksem(sem);
cout<<"\n\tBranch: ";
gets(branch);
checkbranch(branch);
cout<<"\n\tAddress: ";
gets(address);
}
void checksem(char arr[])
{
int x=0;
if((strcmp(arr,"1")==0)||(strcmp(arr,"2")==0)||(strcmp(arr,"3")==0)||(strcmp(arr,"4")==0)||(strcmp(arr,"5")==0)||(strcmp(arr,"6")==0)||(strcmp(arr,"7")==0)||(strcmp(arr,"8")==0))
x=1;
if(x==0)
{
cout<<"\n\tInvalid sem. Re-enter: ";
gets(arr);
checksem(arr);
}
}
void checkusn(char string[])
{
fstream ftemp;
char temp[20], tempusn[20], usn[20];
int i;
if((strlen(string)!=10)||(!isdigit(string[0]))||(!isdigit(string[3]))||(!isdigit(string[4]))||(!isdigit(string[7]))||(!isdigit(string[8]))||(!isdigit(string[9]))||(!isalpha(string[1]))||(!isalpha(string[2]))||(!isalpha(string[5]))||(!isalpha(string[6])))
{
cout<<"\n\tInvalid USN. Re-enter: ";
gets(string);
checkusn(string);
}
file.open("studentdb.txt",ios::in|ios::binary);
while(file.read(temp,120))
{
i=0;
while((tempusn[i]=temp[i])!='|')
i++;
tempusn[i]='\0';
if(strcmp(tempusn,string)==0)
{
cout<<"\n\tUSN already exists. Re-enter: ";
gets(string);
checkusn(string);
}
}
file.close();
}
void student::display()
{
cout<<setiosflags(ios::left);
cout<<setw(15)<<usn<<setw(20)<<name<<setw(10)<<sem<<setw(15)<<branch<<setw(25)<<address;
}
class fixedlength:public iobuffer
{
public: char buffer[120];
void pack(student s);
void unpack(student s);
};
void fixedlength::pack(student s)
{
strcpy(maxbyte, "");
strcpy(maxbyte, s.usn);
strcat(maxbyte,"|");
strcat(maxbyte, s.name);
strcat(maxbyte, "|");
strcat(maxbyte, s.sem);
strcat(maxbyte, "|");
strcat(maxbyte, s.branch);
strcat(maxbyte, "|");
strcat(maxbyte, s.address);
strcat(maxbyte, "#");
}
void fixedlength::unpack(student s)
{
strcpy(buffer, maxbyte);
for(int i=0, j=1, k=0; j<=5; i++, j++)
{
switch(j)
{
case 1: while(buffer[i]!='|')
s.usn[k++]=buffer[i++];
s.usn[k]='\0';
k=0;
break;
case 2: while(buffer[i]!='|')
s.name[k++]=buffer[i++];
s.name[k]='\0';
k=0;
break;
case 3: while(buffer[i]!='|')
s.sem[k++]=buffer[i++];
s.sem[k]='\0';
k=0;
break;
case 4: while(buffer[i]!='|')
s.branch[k++]=buffer[i++];
s.branch[k]='\0';
k=0;
break;
case 5: while(buffer[i]!='\0')
s.address[k++]=buffer[i++];
s.address[k]='\0';
k=0;
}
}
}
class delim:public fixedlength
{
public: void writerecord(student);
void readrecord(student);
void deleterecord(student, char*);
void searchrecord(student, char*);
void modifyrecord(student, char*);
};
void delim::writerecord(student s)
{
pack(s);
file.open("studentdb.txt", ios::app|ios::binary);
file.write((char*)&maxbyte, sizeof(maxbyte));
file.close();
}
void delim::readrecord(student s)
{
file.open("studentdb.txt", ios::in|ios::binary);
cout<<"\n\n File Contents\n\n";
while(file.read((char*)&maxbyte, sizeof(maxbyte)))
{
unpack(s);
cout<<endl;
s.display();
}
getch();
file.close();
}
void delim::searchrecord(student s, char *key)
{
int flag=0;
file.open("studentdb.txt",ios::in|ios::binary);
while((file.read((char*)&maxbyte,sizeof(maxbyte)))&&flag==0)
{
unpack(s);
if(!strcmp(s.usn,key))
{
flag=1;
s.display();
}
}
if(flag==0)
{
cout<<"\n\tSpecified record doesn't exist";
getch();
file.close();
}
}
void delim::deleterecord(student s, char *a)
{
int flag=0;
char x;
fstream ftemp;
file.open("studentdb.txt",ios::in|ios::binary);
ftemp.open("temp.txt", ios::out|ios::trunc|ios::binary);
cout<<"\n\tAre you sure you want to delete (y/n)?";
cin>>x;
if(x=='y'||x=='Y')
{
while(file.read((char*)&maxbyte, sizeof(maxbyte)))
{
unpack(s);
if(strcmp(s.usn,a)==0)
flag=1;
else
ftemp.write((char*)&maxbyte,sizeof(maxbyte));
}
}
if(flag==1)
{
file.close();
ftemp.close();
remove("studentdb.txt");
rename("temp.txt","studentdb.txt");
}
if(flag==0)
{
cout<<"\n\tThe specified record is not found\n";
file.close();
ftemp.close();
}
}
void delim::modifyrecord(student s, char *a)
{
int flag=0, choice;
file.open("studendb.txt",ios::in|ios::out|ios::binary);
while(file.read((char*)&maxbyte,sizeof(maxbyte)))
{
unpack(s);
if(strcmp(s.usn,a)==0)
{
char x;
flag=1;
cout<<"\n\t Current contents: \n\n\n";
s.display();
do
{
cout<<"What do you want to change: ";
cout<<"\n\t1.Name\n\t2. Sem\n\t3. Branch\n\t4. Address\n\t5. Confirm changes\n\t6. Return to main\n";
cout<<"Enter choic: ";
cin>>choice;
switch(choice)
{
case 1: s.rname(); break;
case 2: s.rsem(); break;
case 3: s.rbranch(); break;
case 4: s.raddress(); break;
case 5: break;
case 6: return;
default: cout<<"Invalid option\n";
}
}while(choice==1||choice==2||choice==3||choice==4);
cout<<"\n\tDo you want to modify (y\n)?";
cin>>x;
if(x=='y'||x=='Y')
{
pack(s);
file.seekg(-120,ios::cur);
file.write((char*)&maxbyte,sizeof(maxbyte));
}
else
break;
}
}
if(flag==0)
{
cout<<"\n\t Specified record doesn't exist\n";
file.close();
}
}
void main()
{
clrscr();
iobuffer i;
student s;
fixedlength f;
delim d;
int option;
char no[20], key[20];
for(;;)
{
cout<<"\n\nMenu:- ";
cout<<"\n\t1. Insert\n\t2. Display\n\t3. Delete\n\t4. Modify\n\t5. Search\n\t6. End\n\t";
cin>>option;
switch(option)
{
case 1: s.read();
d.writerecord(s);
break;
case 2: d.readrecord(s);
break;
case 3: cout<<"Enter the usn to delete\n";
gets(no);
d.deleterecord(s, no); break;
case 5: cout<<"\nEnter usn to be searched\n";
gets(key);
d.searchrecord(s,key);
break;
case 4: cout<<"\n\tEnter the usn to be modified\n";
gets(no);
d.modifyrecord(s,no);
break;
case 6: exit(0); break;
}
}
}
I wasn't sure what the error would be therefore I tried:
Reordering the function prototypes statements (even then error would
only be for checkbranch)
Writing the function prototype for checkbranch elsewhere (again error would occur)
Removing the prototype itself (and then get the compilation error for lack of
prototype)

Answer 1

You have to implement the checkbranch function, compiler can not do that for you.