I wrote this piece of code, but cases 2 and 3 seem to have a problem. As noted in the title I think it has to do with unsigned long operations, but I can't understand what it is exactly.
*Edited version (scanf changes).
#include <stdio.h>
int main()
{
int pin, inp, count=0;
unsigned dep=100, add, withdraw;
start:;
if (count>0)
{
printf("\n");
}
printf("Please, input your PIN number:");
scanf("%i", &pin);
while (5)
{
if (pin==2014)
{
printf("To view your deposit, press 1.\n");
printf("To add money to your deposit, press 2.\n");
printf("To withdraw money from your deposit, press 3.\n");
printf("To log off, press 4.\n");
scanf("%i", &inp);
switch(inp)
{
case 1:
printf("The remainder of your deposit is %i.\n\n", dep);
break;
case 2:
printf("Enter the amount of money you want to add: ");
scanf("%u", add);
dep+=add;
break;
case 3:
printf("Enter the amount of money you want to withdraw. We would like to remind you that it should be multiple of 20.\n");
scanf("%u", withdraw);
if(((withdraw)%20==0)&&(withdraw<dep))
{
dep-=withdraw;
}
else
{
printf("We are sorry, but you either chose an invalid withdraw amount or you tried to withdrw more money than you have deposited.\n");
}
break;
case 4:
printf("Logging off.\n");
goto end;
break;
}
}
else
{
printf("You entered an invalid PIN.");
count++;
goto start;
}
}
end:;
}
You're not using scanf correctly.
scanf("%lu", add);
For "%lu" it expects a pointer to an unsigned long int, but what you're passing is not a pointer and not an unsigned long int.
Try:
scanf("%u", &add);
Or change add's type.
I'd also recommend checking scanf's returned value.
See: Value returned by scanf function in c
Related
I might be giving more than enough but long story short I am working on an ATM machine program and I am trying to put the "switch" statement in the main function inside a loop so the user can get more transactions.
I am running into a problem where I would deposit 100 but then when I check the balance it is still at 0. I know everything else works fine but that loop is killing me, I would appreciate any help!
Don't mind all of the extra stuff it is just there to give an idea on what i am working on
int main ()
{
char option;
float balance ;
int count = 1;
option = displayMenu();
do
{
switch (option)
{
case 'D':
getDeposit(balance);
main();
count++;
break;
case 'W':
getWithdrawal(balance);
main();
count++;
break;
case 'B':
displayBalance(balance);
main();
count++;
break;
case 'Q':
printf("Thank you!");
break;
main();
}
} while ( count <= 5);
return 0;
}
char displayMenu()
{
char option;
printf("\n Welcome to HFC Federal Credit Union \n");
printf("\n Please select from the following menu: \n ");
printf("\n D: Make a deposit \n ");
printf("\n W: Make a withdrawal \n ");
printf("\n B: Check your account balance \n ");
printf("\n Q: To quit \n ");
scanf("\n%c" , &option);
return option;
}
float getDeposit(float balance)
{
float deposit;
printf("\n Please enter the amount you want to deposit! ");
scanf("%f" , &deposit);
balance += deposit;
return balance;
}
float getWithdrawal(float balance)
{
float withdrawal;
printf("\n Please enter the amount you want to withdraw! ");
scanf("%f" , &withdrawal);
balance -= withdrawal;
return balance;
}
void displayBalance(float balance)
{
printf("\n Your current balance is %f " , balance);
}
You're recursively calling main() on every iteration of the loop. Just remove this call, and you should be good to go.
You'll also need to assign the return values of your functions to balance, otherwise they won't be able to affect its value.
There are a number of issues with this code... Here are my main pointers (but not all of them, I'm just answering the question):
You're calling main over and over again, for simplicity, you could consider this as restarting the application every time (except for stack issues, that I'm ignoring and other nasty side effects).
You didn't initialize the balance (and friends) variables. They might contain "junk" data.
You're ignoring the return values from the functions you use. If you're not using pointer, you should use assignment.
Your menu printing function is out of the loop... I doubt if that's what you wanted.
Here's a quick dirty fix (untested):
int main() {
char option;
float balance = 0;
int count = 1;
do {
option = displayMenu(); // moved into the loop.
switch (option) {
case 'D':
balance = getDeposit(balance);
count++;
break;
case 'W':
balance = getWithdrawal(balance);
count++;
break;
case 'B':
balance = displayBalance(balance);
count++;
break;
case 'Q':
printf("Thank you!");
break;
}
} while (count <= 5);
return 0;
}
char displayMenu(void) {
char option;
printf("\n Welcome to HFC Federal Credit Union \n");
printf("\n Please select from the following menu: \n ");
printf("\n D: Make a deposit \n ");
printf("\n W: Make a withdrawal \n ");
printf("\n B: Check your account balance \n ");
printf("\n Q: To quit \n ");
scanf("\n%c", &option);
return option;
}
float getDeposit(float balance) {
float deposit;
printf("\n Please enter the amount you want to deposit! ");
scanf("%f", &deposit);
balance += deposit;
return balance;
}
float getWithdrawal(float balance) {
float withdrawal;
printf("\n Please enter the amount you want to withdraw! ");
scanf("%f", &withdrawal);
balance -= withdrawal;
return balance;
}
void displayBalance(float balance) {
printf("\n Your current balance is %f ", balance);
}
Good Luck!
I think the main problem is the update of the switch control variable outside the loop.
Reacting to "Q" with ending is somewhat necessary... then only allowing 5 becomes unneeded.
I fixed several other things, too; and provided comments on them.
And I improved testability a little (5->6). I kept the counting, just extended to 6, in order to allow a complete test "D 100 , B, W 50, B ,Q".
Nice design by the way, to return the balance from the functions, instead of using pointers or global variable. But you need to use the return value instead of ignoring it.
/* include necessary headers, do not skip this when making your MCVE */
#include <stdio.h>
/* prototypes of your functions,
necessary to avoid the "immplicitly declared" warnigns
when compiling "gcc -Wall -Wextra"; which you should
*/
char displayMenu(void);
float getDeposit(float balance);
float getWithdrawal(float balance);
void displayBalance(float balance);
/* slightly better header of main, with "void" */
int main (void)
{
char option;
float balance=0.0; /* initialise your main variable */
int count = 1;
/* your very important update of the switch control variable has been moved ... */
do
{
option = displayMenu(); /* ...here */
/* If you do not update your switch variable inside the loop,
then it will forever think about the very first command,
this explains most of your problem.
*/
switch (option)
{
case 'D':
balance=getDeposit(balance); /* update balance */
/* removed the recursive call to main(),
it is not needed as a solution to the problem that the program
always uses the first command (when updating inside the loop)
and otherwise just makes everything much more complicated and
risky.
*/
count++;
break;
case 'W':
balance=getWithdrawal(balance); /* update balance */
count++;
break;
case 'B':
displayBalance(balance);
count++;
break;
case 'Q':
printf("Thank you!");
/* adding a way to get out of the loop,
using a magic value for the count,
this is a mehtod frowned upon by most,
but it minimises the changes needed to your
own coding attempt.
*/
count=0;
break;
}
} while ( (count <= 6)&&(count>0) ); /* additionally check for the magic "Q" value
check against count<=6, to allow testing D,B,W,B,Q */
return 0;
}
/* use explicitly empty parameter list for functions */
char displayMenu(void)
{
char option;
printf("\n Welcome to HFC Federal Credit Union \n");
printf("\n Please select from the following menu: \n ");
printf("\n D: Make a deposit \n ");
printf("\n W: Make a withdrawal \n ");
printf("\n B: Check your account balance \n ");
printf("\n Q: To quit \n ");
scanf("\n%c" , &option);
return option;
}
float getDeposit(float balance)
{
float deposit;
printf("\n Please enter the amount you want to deposit! ");
scanf("%f" , &deposit);
balance += deposit;
return balance;
}
float getWithdrawal(float balance)
{
float withdrawal;
printf("\n Please enter the amount you want to withdraw! ");
scanf("%f" , &withdrawal);
balance -= withdrawal;
return balance;
}
void displayBalance(float balance)
{
printf("\n Your current balance is %f " , balance);
}
you haven't changed the variable in main().
you can change the loop to this:
do
{
switch (option)
{
case 'D':
balance = getDeposit(balance);
count++;
break;
case 'W':
balance = getWithdrawal(balance);
count++;
break;
case 'B':
displayBalance(balance);
count++;
break;
case 'Q':
printf("Thank you!");
break;
}
} while (count <= 5);
What seems to be the problem in my code? I wish to make a program that makes allows the user to choose from a list of choices/menu. The user chooses one and a function runs. After the function executes the menu appears again until the user decides to quit.
My code is as follows:
#include <stdio.h>
#include <stdlib.h>
int evaluate(int num);
int binaryPrinter(int dec);
int hexaPrinter(int dec);
int militaryTime(int hh, int mm);
int main(void)
{
int choice, x, y;
do {
printf("Type the number of your choice:\n1: Place value evaluation\n2: Convert a Decimal to Binary\n3: Convert a Decimal to Hexadecimal\n4: Convert Standard time to Military time\nEnter Number of Choice: ");
scanf("%d, &choice");
(void) getchar();
switch (choice){
case 1:
printf("Enter number to be evaluated:");
scanf("%d, &x");
int evaluate(int x);
break;
case 2:
printf("Enter a decimal number: ");
scanf("%d, &x");
int binaryPrinter(int x);
break;
case 3:
printf("Enter a decimal number: ");
scanf("&d, &x");
int hexaPrinter(int x);
break;
case 4:
printf("Enter time in standard format: ");
scanf("%d:%d, &x, &y");
int militaryTime(int x, int y);
break;
default:
printf("Invalid choice. Please choose only among the choices.");
}
}while(choice != 5);
return 0;
}
This is what is displayed after inputing the number of choice: Process returned -1073741819 <0xC0000005>
-EDIT-
I have recognized the mistake I have made. But the result's still the same.
here's my new code, but same error: Process returned -1073741819 <0xC0000005>
#include <stdio.h>
#include <stdlib.h>
int evaluate(int num);
int binaryPrinter(int dec);
int hexaPrinter(int dec);
int militaryTime(int hh, int mm);
int main(void)
{
int choice, x, y;
do {
printf("Type the number of your choice:\n1: Place value evaluation\n2: Convert a Decimal to Binary\n3: Convert a Decimal to Hexadecimal\n4: Convert Standard time to Military time\nEnter Number of Choice: ");
scanf("%d", &choice);
(void) getchar();
switch (choice){
case 1:
printf("Enter number to be evaluated:");
scanf("%d", &x);
evaluate(x);
break;
case 2:
printf("Enter a decimal number: ");
scanf("%d", &x);
binaryPrinter(x);
break;
case 3:
printf("Enter a decimal number: ");
scanf("%d", &x);
hexaPrinter(x);
break;
case 4:
printf("Enter time in standard format: ");
scanf("%d:%d", &x, &y);
militaryTime(x, y);
default:
printf("Invalid choice. Please choose only among the choices.");
}
}while(choice != 5);
return 0;
}
Try this code
#include <stdio.h>
#include <stdlib.h>
int evaluate(int num);
int binaryPrinter(int dec);
int hexaPrinter(int dec);
int militaryTime(int hh, int mm);
int main(void)
{
int choice, x, y;
do
{
printf("Type the number of your choice:\n1: Place value evaluation\n2: Convert a Decimal to Binary\n3: Convert a Decimal to Hexadecimal\n4: Convert Standard time to Military time\nEnter Number of Choice: ");
scanf("%d", &choice);
(void) getchar();
switch (choice){
case 1:
printf("Enter number to be evaluated:");
scanf("%d", &x);
evaluate(x);
break;
case 2:
printf("Enter a decimal number: ");
scanf("%d", &x);
binaryPrinter(x);
break;
case 3:
printf("Enter a decimal number: ");
scanf("&d", &x);
hexaPrinter( x);
break;
case 4:
printf("Enter time in standard format: ");
scanf("%d:%d", &x, &y);
militaryTime( x, y);
break;
default:
printf("Invalid choice. Please choose only among the choices.");
}
}while(choice != 5);
return 0;
}
You have used wrong syntax of the scanaf()
it's not like scanf("%d,&choice");
it is like scanf("%d",&choice);
And also missed the syntax of function call
it's not like int evaluate(int x); it is like evaluate(x)
Your scanf statements are all wrong. It usually takes to parameters. A format string containing format specifiers to determine what kind of value and how many values to read and a pointer to the variable were to store the read value (multiple pointers in case of multiple specifiers).
// What you got so far
scanf("%d, &choice"); // <-- format string and pointer to variables are combined
// How it should look like
scanf("%d", &choice); // format string "%d" containing 1 format specifier to read an int
// and a pointer to the variable choice to store the read value
Ok now to the next mistake. When declaring a function you need to write down the whole function header (returnType functionName(ParameterType1 Parameter1, ParameterType2 Parameter2, ...)) however when you want to call that funtion all it needs is its name and the parameters BUT whithout theire type.
So declaring a function like this int evaluate(int num) like you did at the very beginning of your code is fine but when calling it in your switch all it needs is the name (evaluate) and the values, or variables you want to pass to the function as parameters (evaluate(x)).
So now all together:
printf("Type the number of your choice:\n1: Place value evaluation\n2: Convert a Decimal to Binary\n3: Convert a Decimal to Hexadecimal\n4: Convert Standard time to Military time\nEnter Number of Choice: ");
scanf("%d", &choice); // scan an integer value and store it in choice
switch (choice)
{
case 1:
printf("Enter number to be evaluated:");
scanf("%d", &x);
evaluate(x);
break;
case 2:
...
}
I am writing a program that can calculate the areas of a square, cube, and circle. The program needs to present an error message and allow the user to enter a new choice if they enter something not included in the menu. My problem is that if they type anything includes my menu options then the program still executes. (i.e. -1, 23, 344) I was wondering how to get it to ignore anything after the first character or to read the whole string. Or if there is something better than getchar(). I'm open to any solutions! Thank you!
#include <stdio.h>
#include <stdlib.h>
int main(void) {
int choice;
int lengthsq;
int areasq;
int lengthcube;
int areacube;
int radius;
double circlearea;
printf("Area Calculation\n");
printf("(1) Square\n");
printf("(2) Cube\n");
printf("(3) Circle\n");
fputs("Please make a selction: ", stdout);
while((choice = getchar()) != '\n')
switch (choice) {
case '1':
printf("\nPlease enter the length: ");
scanf("%d", &lengthsq);
while(lengthsq <= 0){
printf("Error! Please enter a positive number: ");
scanf("%d", &lengthsq);
}
areasq = lengthsq * lengthsq;
printf("The area of the square is %d.", areasq);
return 0;
case '2':
printf("\nPlease enter the length: ");
scanf("%d", &lengthcube);
while (lengthcube <= 0) {
printf("Error! Please enter a positive number: ");
scanf("%d", &lengthcube);
}
areacube = 6 * lengthcube * lengthcube;
printf("The surface area of the cube is %d.\n", areacube);
return 0;
case '3':
printf("\nPlease enter the radius: ");
scanf("%d", &radius);
while(radius <= 0){
printf("Error! Pleae enter a postive number: ");
scanf("%d", &radius);
}
circlearea = 3.14159 * radius * radius;
printf("The area of the circle is %.2f.\n", circlearea);
return 0;
case '\n':
case '\t':
case ' ':
break;
default:
printf("\nInvalid choice entered.\n");
fputs("Enter a new choice: ", stdout);
break;
}
}
You could add another switch case for the dash, which would toggle some kind of negative flag and then read a number as you're already doing. If you do not like introducing such a flag, then the best option would be using fgets, which returns the entire input line. But that has the downside that you need to parse the input. I.e. do some string manipulation, which may be slightly more complex than a simple flag parameter.
On the other hand, from the code you attached, I deduct that the only valid input consists of mere numbers (integers). You could just read an integer then with scanf.
I have some code, but I'll shorten it to show only the relevant parts.
// Displays the list of user’s options available
//Displays the user’s selections and sets the value of the choice
void mainMenu(int *choice);
//Displays the types of account they would like to access and sets the
//value of the chosen account type
void AccountMenu(char *typeAcct);
//Prompts the user for the amount of their deposit and updates the selected account
void DepositMoney(double *currBal);
//Asks the user if they want another transaction
void Repeat(char * doAgain);
int main(){
int choice = 0;
char repeat = 'y';
double checkBal = 575.0,
saveBal = 3750.0,
credBal = 450.0;
char typeAcct;
while(repeat!='n'){
mainMenu(&choice); //get action from user
AccountMenu(&typeAcct); //get account to perform action on from user
switch (choice){
case 1:
switch (typeAcct){
case 'c':
DepositMoney(&checkBal);
break;
case 's':
DepositMoney(&saveBal);
break;
case 'r':
DepositMoney(&credBal);
break;
} //case 1
break;
}
Repeat(&repeat);
repeat = tolower(repeat);
}
}
// Displays the list of user’s options available
//Displays the user’s selections and sets the value of the choice
void mainMenu(int *choice){
printf("Bank Program\n\n");
printf("Please enter your choice:\n");
printf("[1] Deposit\n");
printf("[2] Withdraw\n");
printf("[3] Balance Inquiry\n\n >> ");
scanf(" %d", choice);
}
//Displays the types of account they would like to access and sets the
//value of the chosen account type
void AccountMenu(char *typeAcct){
char choice;
printf("Please enter your choice:\n");
printf("[C] Checking\n");
printf("[S] Savings\n");
printf("[R] Credit\n\n >> ");
scanf(" %c", &choice);
*typeAcct = tolower(choice);
}
//Prompts the user for the amount of their deposit and updates the selected account
void DepositMoney(double *currBal){
printf("Depositing money.\nHow much would you like to deposit?\n\n >> ");
double amount = 0; //deposit amount
scanf(" &f", &amount);
*currBal = *currBal + amount;
}
void Repeat(char * doAgain){
printf("Would you like to perform another transaction? (y/n)\n\n >> ");
scanf(" &c", doAgain);
}
When I execute this code, it runs mostly fine. For example, if I enter "1" for mainMenu and "c" for AccountMenu, choice and typeAcct are both indeed set to "1" and "c" respectively.
The problem doesn't seem to be with the loop. I've tried taking out the loop and only running it once and it still doesn't work. What happens is that after inputting the amount of money I would like to deposit, the value of the variable isn't updated and mainMenu and AccountMenu are run again (even when DepositMoney is the last line of code in the main function and there is no loop). Why does this happen?
1) Incorrect scanf() usage
double amount = 0;
// scanf(" &f", &amount);
scanf(" %lf", &amount);
// scanf(" &c", doAgain);
scanf(" %c", doAgain);
2) Insure your compiler warning are fully enabled. This is the most important bit as most problems are quickly identified this way.
3) Always check the return value of scanf(). BTW, the leading space in " %f" is not needed as "%f" scans over leading white-space anyways. Good though, to have with " %c".
if (scanf("%lf", &amount) != 1) Handle_Error();
4) tolower() take an int. In the rare siuation where a user enters a char in the range \x80 to \xFF, the conversion of char to int is a sign extend and likely a negative number. Unfortunately, this does not work for tolower() which is well defined for 0 to 255 and EOF, but not other negative values.
// repeat = tolower(repeat);
repeat = tolower((unsigned char) repeat);
...
// *typeAcct = tolower(choice);
*typeAcct = tolower((unsigned char) choice);
I am trying to compile a small bank program in C in visual studio 2012 express. It shows me this error "undeclared identifier" for almost all variables and this one too "syntax error: missing ';' before 'type'".Please tell me the correct syntax.Thank you.
#include<stdio.h>
#include<conio.h>
int main()
{
printf("Welcome to skybank\n");
int deposit,withdraw,kbalance;
char option;
printf("Press 1 to deposit cash\n");
printf("Press 2 to Withdraw Cash\n");
printf("Press 3 to Know Your Balance\n");
scanf_s("%c",option);
int decash,wicash;
switch(option)
{
int balance;
printf("Enter your current Balance\n");
scanf_s("%d",&balance);
case 1:
printf("Enter the amount you want to deposit\n");
scanf_s("%d",&decash);
printf("Thank You\n");
printf("%d have been deposited in your account\n",decash);
break;
case 2:
printf("Enter the amount you want to withdraw\n");
scanf_s("%d",&wicash);
int wibal;
wibal=balance-wicash;
printf("Thank You\n");
printf("%d have been withdrawed from your account\n",wicash);
printf("Your balance is %d\n",wibal);
break;
case 3:
printf("Your balance is Rs.%d\n",balance);
break;
default:
printf("Invalid Input\n");
break;
}
getchar();
}
The Microsoft C compiler only supports a 25 year old version of the language. And one of the limitations is that all variables must be declared before any other statements. So move all your variable declarations to the top of the function.
The next error I can see is the use of scanf_s with the %c format string. You must pass a pointer to the variable, and pass the number of characters to read.
scanf_s("%c", &option, 1);
And likewise you need to pass an address for the read of balance.
You also need to change the switch statement so that it just contains cases. Move the bare instructions outside.
Your reading of option won't work. Because when you check for 1 you are checking for the character with ASCII code 1. Change option to be an int and read using %d.
Perhaps you are looking for something like this:
#include<stdio.h>
#include<conio.h>
int main(void)
{
int deposit,withdraw,kbalance;
int option;
int decash,wicash;
int balance;
int wibal;
printf("Welcome to skybank\n");
printf("Press 1 to deposit cash\n");
printf("Press 2 to Withdraw Cash\n");
printf("Press 3 to Know Your Balance\n");
scanf_s("%d", &option);
printf("Enter your current Balance\n");
scanf_s("%d", &balance);
switch(option)
{
case 1:
printf("Enter the amount you want to deposit\n");
scanf_s("%d", &decash);
printf("Thank You\n");
printf("%d have been deposited in your account\n", decash);
break;
case 2:
printf("Enter the amount you want to withdraw\n");
scanf_s("%d", &wicash);
wibal=balance-wicash;
printf("Thank You\n");
printf("%d have been withdrawed from your account\n", wicash);
printf("Your balance is %d\n", wibal);
break;
case 3:
printf("Your balance is Rs.%d\n", balance);
break;
default:
printf("Invalid Input\n");
break;
}
getchar();
}
Regarding the unidentified variables, try putting all declarations of variables at the top of the main block, something like:
int main()
{
int deposit, withdraw, kbalance, decash, wicash, wibal;
char option;
printf("Welcome to skybank\n");
Older variants of C frown upon mixing variable declarations with code. To my knowledge the C standard of Microsoft's C implementation is pre-C99 so perhaps this could be the issue.
A few other issues that you should look into:
scanf_s("%c",option); - option should be &option as you are taking a pointer to that variable.
Also here: case 1:
You want '1' (as in case '1') instead of plain 1 as it is a char, not an int you want.
Same for the other case checks.
With regards to the scanf_s problems, try compiling with warnings, it should have been pointed out by the compiler.
Finally, you might want to rid your code of the variables you're not using such as kbalance, withdraw and deposit.
do at the beginning of the block in the declaration of the variable for visual c.
E.g.
int main()
{
int deposit,withdraw,kbalance;
char option;
int decash,wicash
int balance;
int wibal;
...
try this code:
#include<stdio.h>
#include<stdlib.h>
int main()
{
printf("Welcome to skybank\n");
int deposit,withdraw,kbalance;
char option;
printf("Press 1 to deposit cash\n");
printf("Press 2 to Withdraw Cash\n");
printf("Press 3 to Know Your Balance\n");
scanf("%c",&option);
int decash,wicash;
switch(option)
{
int balance;
printf("Enter your current Balance\n");
scanf("%d",&balance);
case 1:
printf("Enter the amount you want to deposit\n");
scanf("%d",&decash);
printf("Thank You\n");
printf("%d have been deposited in your account\n",decash);
break;
case 2:
printf("Enter the amount you want to withdraw\n");
scanf("%d",&wicash);
int wibal;
wibal=balance-wicash;
printf("Thank You\n");
printf("%d have been withdrawed from your account\n",wicash);
printf("Your balance is %d\n",wibal);
break;
case 3:
printf("Your balance is Rs.%d\n",balance);
break;
default:
printf("Invalid Input\n");
break;
}
getchar();
}
Move this:
int balance;
printf("Enter your current Balance\n");
scanf_s("%d",&balance);
Before the switch statement.