Well, in order to actually read through the code you should first indent properly. Pick an indenting style that works and stick with it. Most people don't care what type of style you use as long as you're consistent and it doesn't look like slop. Otherwise, it will be difficult for you and others to read and understand your code.
For portability, and in general, good programming practices, I would suggest you consider the following:
- Don't be dependent upon getch(), clrscr(), or conio.h. You will not be able to use them on all systems.
- Don't use void main(). This is not allowed by the C standard except on specific systems (which if you're running Windows XP, that doesn't include your situation).
- Don't use global variables except in places where you really need them. This limits your functions and is more open to error.
- Don't mix and match types. If you have a long int, use a long int specifier in your printf() and scanf() functions. Mixing and matching is just inviting issues.
As far as your actual problem goes, because of the lack of proper indention, I'm having trouble reading and understanding your code. Because of your lack of portability, I'm unable to currently run your code with my favorite compiler.
BTW, why oh why would you do something so stupid as to name the functions totally different than what they actually do? Are you some sort of sadist that wants to torture programmers like me? 
This shouldn't be an obfuscation lesson here.
Your problem is here:
Code:
if(a[i].amt-amt<0)
printf("\n Negative Balance! ");
else
{
printf("\n Enter the Amt you want to withdraw: ");
scanf("%ld",&amt);
a[i].amt=a[i].amt-amt;
printf("\n %ld Rs withdrawn ",amt);
printf("\n New balance is: %ld",a[i].amt);
}
You're using the value of amt before amt is even set to anything valid. Therefore it contains random garbage that you're performing math operations with. This will randomly cause issues.
Fixing a lot of the garbage in your program, this is what I came up with:
Code:
#include<stdio.h>
/*#include<conio.h>*/
void withdr(int acc,int n);
void dep(int acc,int n);
void bal(int acc,int n);
struct bank
{
int acc;
long int amt;
}a[10];
int main()
{
int i,j,w1=0,temp,n,op,acc/*,amt*/;
/*clrscr();
*/
printf("\n Enter the number of acc numbers : ");
scanf("%d",&n);
for(i=0;i<n;i++)
{
w1=0;
printf("\n Enter the acc number: ");
scanf("%d",&temp);
for(j=0;j<i;j++)
{
if(temp==a[j].acc)
{
w1=1;
break;
}
}
if(w1==1)
{
printf("\n Acc No already exist! ");
i--;
}
else
{
a[i].acc=temp;
printf("\n Enter the Amount: ");
scanf("%ld",&a[i].amt);
}
}
do
{
/*getch();
clrscr();
*/
printf("\n Select the operation you want to perform: ");
printf("\n 1.Balance \n 2.Withdraw \n 3.Deposit \n 4.Exit\n");
printf("Enter your Option:");
scanf("%d",&op);
if(op!=4)
{
printf("\n Enter the acc no: ");
scanf("%d",&acc);
}
switch(op)
{
case 1:
withdr(acc,n);
break;
case 2:
dep(acc,n);
break;
case 3:
bal(acc,n);
break;
case 4:
break;
default:printf("\n Enter a value between 1 and 4");
}
}while(op!=4);
/*getch();
*/
return 0;
}
void withdr(int acc,int n)
{
int w=0,i;
for(i=0;i<n;i++)
{
if(acc==a[i].acc)
{
w=1;
printf("\n The balance in the acc no %d is "
"%ld",a[i].acc,a[i].amt);
}
}
if(w==0)
printf("\n Wrong Account number! ");
}
void dep(int acc,int n)
{
int i=0,w=0;
long int amt;
for(i=0;i<n;i++)
{
if(acc==a[i].acc)
{
w=1;
break;
}
}
if(w==0)
{
printf("\n Wrong Account number! ");
}
else
{
printf("\n Enter the Amt you want to withdraw: ");
scanf("%ld",&amt);
if(a[i].amt-amt<0)
{
printf("\n Negative Balance! ");
}
else
{
a[i].amt=a[i].amt-amt;
printf("\n %ld Rs withdrawn ",amt);
printf("\n New balance is: %ld",a[i].amt);
}
}
}
void bal(int acc,int n)
{
int i=0,w=0;
long int amt;
for(i=0;i<n;i++)
if(acc==a[i].acc)
{
w=1;
break;
}
if(w==0)
printf("\n Wrong Account number! ");
else
{
printf("\n Enter the amt you want to Deposit: ");
scanf("%ld",&amt);
a[i].amt=a[i].amt+amt;
printf("\n %ld Rs Deposited ",amt);
printf("\n New balance is: %ld",a[i].amt);
}
}
I'm not in a good enough mood to clean it up totally, but this is enough that it appears to work and it compiles with MinGW without any errors (that I could raise anyway).
C program - Kindly help
