a simple program

[JDmac]

I am writing this simple program of depositting and withdrawing an amount a printing the balance.

The program is not working correctly.....Any suggestions

I am not too sure whether I should use double , int or float
and also whether I should use gets fgets, scanf, or sscanf...I think this is where my problem is......


Thanks

#include <stdio.h>
#include<stdlib.h>

int main(void)
{
	double old_balance, balance;
	double deposit, withdraw;
	int choice;
	char line[15];

	balance=0;

	printf("Enter old balance: ");
	gets(line);
	sscanf(line,"%ld",&old_balance);

	for(;;)
	{
		printf("\n   MENU\n");
		printf("   1. deposit\n");
		printf("   2. withdrawal\n");
		printf("   3. quit\n\n");

		printf("   choice: ");

		if (scanf("%d", &choice)==1)
		{
			printf("\nEnter deposit amount: ");
			fscanf(stdin,"%ld",&deposit);
			balance= old_balance + deposit;
			printf("\nNew balance: %ld\n", balance);
		}

		if (scanf("%d", &choice)==2)
		{
			printf("\nEnter deposit amount: ");
			fscanf(stdin,"%ld",&deposit);
			balance= old_balance + deposit;
			printf("\nNew balance: %ld\n", balance);
		}	

		if (scanf("%d", &choice)==3)		
				exit(1);
	}
	
	return 0;
}

[quzah]

It's not working correctly because you're reading three different times. You need to read into the variable and then compare them, not just read one, then another then another.

You're comparing the return value of scanf, not what's in the variable. Try using 1 scanf call, and then using the variable you read into for comparison checks.

Quzah.

[Hammer]

>>gets(line);
Don't use gets(), that's the worst of the lot.

You seem to have a variety of input functions.... I think you should stick to one, maybe fgets(). Use this for getting both text and numbers, then, if you want to convert the input to a number, use something like strtod() to convert to a double, or strtol() to convert to a long int.

Alternatively, if all you are getting are numbers, you might want to learn about scanf(). But you won't need fscanf() or sscanf() in this case.

>>if (scanf("%d", &choice)==1)
>>if (scanf("%d", &choice)==2)
Here you are getting two lots of input, whereas you should be getting one input and testing it against two values.

>>sscanf(line,"%ld",&old_balance);
Using %ld will get you a long int, to get a double, you need %lf.

[edit]beat!

[JDmac]

Thanks for the suggestions...

Here is my updated code......How can I keep on adding a deposit and display each time an updated new_balance.

#include <stdio.h>
#include<stdlib.h>

int main(void)
{
	double old_balance, new_balance;
	double deposit, withdraw;
	int choice;
	char menu[]="   MENU\n   1. deposit\n   2. withdrawal\n   3. quit\n\n";

	printf("Enter old balance: ");
	scanf("%lf",&old_balance);

	for(;;)
	{
		printf("\n%s",menu);
		
		printf("   choice: ");
		scanf("%d", &choice);

		if(choice==1)
		{
			printf("\nEnter deposit amount: ");
			scanf("%lf",&deposit);
			printf("\nNew balance $ %0.2lf\n", old_balance+deposit);
		}

		else if (choice==2)
		{
			printf("\nEnter withdrawal amount: ");
			scanf("%ld",&withdraw);
			printf("\nNew balance $ 0.2%ld\n", new_balance-withdraw);
		}	

		else if (choice==3)	
		{
			puts("\n   Program Terminated");
			exit(1);
		}
	}
	
	return 0;
}

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