I would need some help regarding how to use isdigit() in this example:
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
int main()
{
int usr_option;
do
{
printf("\t\t\t************************MENU***********************\n");
printf("\t\t\t*** 1. Enter Code\t\t\t\t***\n");
printf("\t\t\t*** 2. Encrypt code and verify if correct\t***\n");
printf("\t\t\t*** 3. Decrypt code\t\t\t\t***\n");
printf("\t\t\t*** 4. Display number of times code was enter\t***\n");
printf("\t\t\t***\t\t(i) Successfully\t\t***\n");
printf("\t\t\t***\t\t(i) Unsuccessfully\t\t***\n");
printf("\t\t\t*** 5. Exit Program\t\t\t\t***\n");
printf("\t\t\t***************************************************\n");
printf("\nPlease enter your option from the menu: ");
scanf("%d", &usr_option);
if (isdigit(usr_option))
{
//Inside here is my switch case e.g switch(usr_option){/*code*/}
}
else
{
printf("Need to enter a digit\n");
}
}//end do while
while(usr_option != 5);
return 0;
}
How can I implement this code to not go into an infinite loop?
I've tried different ways but it seems like it doesn't want to work. I use the compilers CodeBlocks and Sublime Text 3.
If you have read a number via scanf("%d", &usr_option); Then you don't need to use is_digit() You can just use if or switch e.g.
switch(usr_option)
{
case 1: enter_code(); break;
case 2: encrypt(); break;
You only need is_digit if you are checking that characters in a string are digits or not.
i.e. '1' != 1
Related
The following code does not execute the last else if statement when you assign to choice value 3.
#include<stdio.h>
#include<stdlib.h>
int main() {
puts("Specify with a number what is that you want to do.");
puts("1. Restore wallet from seed.");
puts("2. Generate a view only wallet.");
puts("3. Get guidance on the usage from within monero-wallet-cli.");
unsigned char choice;
choice = getchar();
if ( choice == '1' ) {
system("nice -19 ~/monero-x86_64-linux-gnu-v0.17.2.0/monero-wallet-cli --testnet --restore-deterministic-wallet");
exit(0);
}
else if ( choice == '2' ) {
system("nice -19 ~/monero-x86_64-linux-gnu-v0.17.2.0/monero-wallet-cli --testnet --generate-from-view-key wallet-view-only");
exit(0);
}
else if ( choice == '3' ) {
puts("Specify with a number what is that you want to do.");
puts("1. Get guidance in my addresses and UTXOs");
puts("2. Pay");
puts("3. Get guidance on mining.");
unsigned char choicetwo = getchar();
if ( choicetwo == '1' ) {
printf("Use \033address all\033 to get all your addresses that have any balance, or that you have generated at this session.");
printf("Use \033balance\033 to get your balance");
printf("Use \033show_transfers\033 to get ");
printf("Use \033show_transfers\033 out to get ");
printf("Use \033show_transfers in\033 to get your balance");
}
}
return 0;
}
I get the following output When I enter 3:
Specify with a number what is that you want to do.
1. Restore wallet from seed.
2. Generate a view only wallet.
3. Get guidance on the usage from within monero-wallet-cli.
3
Specify with a number what is that you want to do.
1. Get guidance in my addresses and UTXOs
2. Pay
3. Get guidance on mining.
I'm really blocked, something is missing and I have no clue why it does not proceed to take the input from the user for the second time.
When you enter "3" for the first input, you're actually inputting two characters: the character '3' and a newline. The first getchar function reads "3" from the input stream, and the second one reads the newline.
After accepting the first input, you'll want to call getchar in a loop until you read a newline to clear the input buffer.
choice = getchar();
while (getchar() != '\n');
How can I make admin function works inside the switch?
I tried doing it but still got an error using Visual Studio 2017
My program is about creating a pharmacy management system that has 2 access as admin and user. Admin can add or update or delete and the user can search or see expiry date.
Error C1075 '': no matching token found
Here is my code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int admin(int1);
int main()
{
char username[50];
int password;
int choice;
int mainmenu = 1;
printf(" \n\n\n\t\t\t\t\tWELCOME TO THE PHARMACY MANAGMENT SYSTEM\t\t\t\t\t");
while (mainmenu == 1) {
printf("\n\n\n\nPlease choose from the current choices\n \n1.ADMIN \n\n2. "
"CUSTOMER\n\n3. EXIT\n\n");
scanf("%d", &choice);
do {
switch (choice) {
case 1:
admin(1);
break;
case 2:
break;
case 3:
printf(
"\n System Closes ...Press Any Key to turn off the system ....");
mainmenu = 0;
break;
}
}
while (choice = 1);
{
printf("\nplease enter your username\t");
scanf("%s", username);
printf("\nplease enter your password\t");
scanf("%d", &password);
if ((strcmp(username, "admin") == 0) && (password == 123123)) {
printf("\n\n\t\t\tYou have logged in succefully....\t\t\n");
break;
} else {
printf("\n\t\tThe username or password is incorrect.\n\t\tPlease "
"verify that CAPS LOCK is not on,and then retype the current "
"username and password.\n\n \a");
}
getch();
return (0);
}
}
You have at least following problems (in decreasing importance):
The final } is missing at the very end of the progran
You havce declared the function int admin(int1) but you havent implemented the function.
int admin(int1) should be declared int admin(int)
the warning for getch is because you forgot to include the conio.h header. This header is Microsoft specific.
Consider also platinum95's answer.
You have some issues with your loops, I think you expect them to do something different.
while (mainmenu == 1)
This loops the program until '3' is entered. This seems fine.
do {
...
}
while (choice = 1);
I think you need to look up how do-while loops work. This loop will never exit, as you assign choice to 1 rather than compare it with 1.
while (choice = 1);
{
...
}
This is not a loop. That while(choice = 1) belongs to the previous do-while loop. You therefore just have a block of code here (which is never executed since the previous loop never exits).
It also seems like the block of code here is intended to be the admin(int) function, (which you didn't include, so I presume this is supposed to be it).
Your best option is to go find a tutorial online of how while and do-while loops work, as well as a tutorial on writing and using functions.
I have an assignment due and I am drawing a blank on what exactly to do... I'm sure it is simple but I havent quite gotten the hang of things yet. The assignment is -
Write a program that gives the user 2 menu options: either call a function that will print a greeting and your name 4 times or call a function that will count down from 10 to 0 and then print "Blastoff!". Both functions should use for loops to print the appropriate output.
I have the prompt and the functions done so far... but I am unsure of how to display one or the other depending on the choice the user makes. Thank you for your help.
#include <stdio.h>
int main (void){
// declare counter variable
int i;
// prompt the user to make a choice
printf("What would you like to do?\n 1. Print my name\n 2. Count down from 10\n");
printf("\n");
// display greeting and name 4 times
for(i=1;i<=4;i++)
{
printf("Hi, my name is Bridget\n");
}
// display countdown
for(i=10;i>=0;--i)
{
printf("%d\n", i);
}
printf("Blastoff!");
}
You should read the input from user's keyboard:
int c;
c = getchar();
if (c == '1')
{
// display greeting and name 4 times
for(i=1;i<=4;i++)
{
printf("Hi, my name is Bridget\n");
}
}
if (c == '2')
{
// display countdown
for(i=10;i>=0;--i)
{
printf("%d\n", i);
}
}
printf("Blastoff!");
you should use Switch case.
switch(choice) {
case 1: //first for loop
break;
case 2: //second for loop
break;
}
Looks like you are missing a couple of points here. Firstly, you have not yet written any functions. Try looking here to gain some insight on that front.
Secondly, to make a choice based on user input you need to actually get that input somehow. You'll probably want to use scanf.
Lastly, once you have the user's input (say, in a variable declared as int input;) you can use if to control the flow of your program based on that variable like this:
if(input == 1){
greet();
}
else {
countDown();
}
Cheers! If you have any further questions feel free to comment below.
First of all you haven't actually declared you functions. Functions in C should be declared like the main function is. For more info in this see here.
// display greeting and name 4 times
void greeting(){
for(i=1;i<=4;i++)
{
printf("Hi, my name is Bridget\n");
}
}
void countdown() {
// display countdown
for(i=10;i>=0;--i)
{
printf("%d\n", i);
}
printf("Blastoff!");
}
To get the user's input the most common way is by keyboard. scanf accomplishes that in C. Details on scanf here
int main(void){
int i, choice;
//prompt the user to make a choice
// You don't need 2 printf for the newlines stick them to one.
printf("What would you like to do?\n 1. Print my name\n 2. Count down from 10\n\n");
//This takes the user's input and puts it in the variable choice
scanf(%d, &choice);
}
Lastly to decide what to do based on the user input you can use either an if then else statement or a switch. I will provide a solution with an if statement and you can figure the one with the switch on your own. Your final code should look like this.
int main(void){
int i, choice;
//prompt the user to make a choice
// You don't need 2 printf for the newlines stick them to one.
printf("What would you like to do?\n 1. Print my name\n 2. Count down from 10\n\n");
//This takes the user's input and puts it in the variable choice
scanf(%d, &choice);
if(choice == 1){
greeting();
}else{
countdown();
}
}
// display greeting and name 4 times
void greeting(){
for(i=1;i<=4;i++)
{
printf("Hi, my name is Bridget\n");
}
}
void countdown() {
// display countdown
for(i=10;i>=0;--i)
{
printf("%d\n", i);
}
printf("Blastoff!");
}
Bear in mind that this code has a lot of flaws (error checking mainly) but I guess your assigment is not about that.
First of all you need to include libraries with function you will need. You do this by
#include <someLibrary.h>
at the beggining of you document. Libraries mostly have .h extension. Always look for them if you try to do something. You consider them to have best performance and functionality as possible (not always true).
What is next you declare your functions. Function has name, arguments which are going into it, body in which they do something and return value (can be float, int, char etc). If function doesnt return anything, they return void (dont have return at the end). You declare functions before main() with only types of arguments. Whole body is after main (it is better looking).
If you declared function with arguments, you have to provide these arguments to function in () brackets. Even if no arguments are needed, you use them like getch() in example below. Note that function become what it return. If you declared some new variables in function they will be visible only in function. On the other hand function will not see any variable from other function (main too). If you want so, declare global variables (not recommended).
#include <stdio.h>
#include <conio.h> //libraries
void function1(int);
float function2(float); //declaration of functions
int main()
{
char decision;
printf("press 'a' to run function1, press 'b' to run function2\n");
decision=getch(); //first see getch()? look in google for functionality and library !
int someInt=10;
float someFloat=11;
if(decision== 'a')
{
function1(someInt);
}
else if(decision == 'b')
{
printf("%f", funcion2(someFloat)); //example that function become what they return
}
else
{
printf("No decision has been made");
}
getch(); //program will wait for any key press
return 0;
}
void function1(int param1)
{
//print your stuff // this function return void, so doesnt have return; statement
}
float function2(float param1)
{
return 2*param1; //this function have to return some float
}
I recently programmed this code (C) for a pretty simple calculator in Xcode.
It works mostly but does not display the answer for the sum/s.
The code is as follows:
#include <stdio.h>
int main()
{
//int's & chars-----------------
char SumMethod;
int firstnumber, secondnumber;
//int's & chars------------------
puts("Calculator v0.6");
printf("Please input first number: "); //Prompts 'firstnumber' input
scanf("%d", &firstnumber); //Scan's 'firstnumber' input and saves to '&firstnumber'
printf("Please input second number: "); //Prompts 'secondnumber' input
scanf("%d", &secondnumber); //Scan's 'secondnumber' input and saves to '&secondnumber
printf("d" "Please select Method: +(a), -(b), *(c), /(d): ");
scanf("%c", &SumMethod); //Scan's 'SumMethod' input
if(SumMethod=='a') {
printf ("%d",firstnumber + secondnumber); //This section detects the SumMethod and outputs the corrisponding sum
}
else if (SumMethod=='b'){
printf("%d",firstnumber-secondnumber);
}
else if (SumMethod=='c') {
printf("%d",firstnumber * secondnumber);
}
else if (SumMethod=='d') {
printf("%d",firstnumber / secondnumber);
}
}
For the solution i'm looking for a response that doesn't drastically change the code as how it is now is what I understand and because i'm relatively new to coding in general however if there is an obvious fix using useful common tools that would be much appreciated.
Thanks, Xenon
Your problem is that your comparisons are wrong. You need to compare your input to the LETTER a and not the (undefined and essentially random) values of the variables a,b,c,d.
so it is
if(SumMethod=='a')
instead of
if(SumMethod==a)
You don't need your variables a,b,c,d at all.
I have a class assignment in C to make a simple calculator that performs three calculations. I haven't completed all of the functions yet but I am having a problem with my calcMenu function. When the function is called the program runs through all of the if else statements and unknown to me, performs only the else statement which is error checking. Than the function is run again which is intended but this time it does not run through all of the if else statements and allows the user to make a choice. I know I have done something really stupid but have been racking my brain for the last hour. If anyone has any pitty for me, than please point me in the right direction. I know all the system calls will Irk some but this is a basic class and our instructor has told us to use them.
Thanks in advance,
Mike
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#define pause system ("pause")
#define cls system ("cls")
//Prototype calculate functions here
void evenOrOdd(int userNumber);
void squareNum(int userNumber);
void cubeNum(int userNumber);
void calcMenu(int userNumber);
void main() {
//Declare local variables here
int userNumber = 0;
printf("\t\t\tThe amazing three function caluculator\n\n\n");
printf("Please enter a whole number that you would like to calculate\n");
scanf("%d", &userNumber);
calcMenu(userNumber);
}
void calcMenu(int userNumber)
{
char calculateOption;
printf("\nWhat calculation would you like to perform with your number?\n\n");
printf("Press A.) to check if your number is even or odd.\n\n");
printf("Press B.) to calculate the square of your number.\n\n");
printf("Press C.) to calculate the cube of your number.\n\n");
printf("press D.) to exit the program.\n");
scanf("%c", &calculateOption);
calculateOption = toupper (calculateOption);
if (calculateOption == 'A')
{
evenOrOdd(userNumber);
}
else if (calculateOption == 'B')
{
squareNum(userNumber);
}
else if (calculateOption == 'C')
{
cubeNum(userNumber);
}
else if (calculateOption == 'D')
{
system("cls");
printf("Thank You for using my amazing calculator.\n\n");
system ("pause");
system ("exit");
}
else
{
printf("Please enter a valid choice");
calcMenu(userNumber);
}
}
void evenOrOdd(int userNumber) {
userNumber = userNumber %2;
if (userNumber == 0)
{
printf("Your number is even. \n");
}
else
{
printf("Your number is odd. \n");
}
}
void squareNum(int userNumber) {
}
void cubeNum(int userNumber){
}
When you read input with scanf you have to press the Enter key to make the program continue. Your scanf call reads the single character from the input, but leaves the Enter key still in the input buffer, to be read next time you call scanf.
There is a very simple trick to solve that: Place a space in the scanf format string before or after the "%c". This will make scanf skip whitespace.
scanf("%c ", &calculateOption);
If you stepped through the code with a debugger you would have easily seen that calculateOption would have been the newline character.
First of all, You can condense all those printf statements into one function to save the extra calls.
Next, you should probably indent your functions, I can't tell where one begins and another ends at a glance.
Third, don't use system("pause"), use getchar().
Fourth, this is optional, you might want to turn those if statements into a switch statement.
Now, on to your question. First of all, instead of using scanf("%c", &calculateOption), just use getchar() here too. In this case, I would write calcMenu() as this:
int calcMenu(int userNumber){
printf("\nWhat calculation would you like to perform with your number?\n\n\
Press A.) to check if your number is even or odd.\n\n\
Press B.) to calculate the square of your number.\n\n\
Press C.) to calculate the cube of your number.\n\n\
Press D.) to exit the program.\n");
switch(toupper(getchar())){
case 'A':
evenOrOdd(userNumber);
break;
case 'B':
squareNum(userNumber);
break;
case 'C':
cubeNum(userNumber);
break;
case 'D':
system("cls"); //this is bad, really.
printf("Thank You for using my amazing calculator.\n\n");
getchar();
return 0;
default:
printf("Please enter a valid choice: ");
calcMenu(userNumber);
break;
}
}
Also, main should always return a value. void main is bad practice.
Disclaimer: The code isn't tested, you shouldn't copy/paste it anyways. I also don't know if you're being forced to use some things or not...