Thread: c menu

in c i need to have a menu.

pretty much

blah blah blah
then after all that executes you prompt for: Go again (y,n) then repeat the above steps.

I want to do it in a DO function btw. I have tried while with strcmp but it only works once then the program quits.

any help?


I can do it with numbers but i cannot get it working for chars.

Ok.. well do is a control statement not a function, first of all. And secondly, a little code goes a long way. Put what you have and I will correct it.

Code is below

char choice[2], choice1[2];

choice1[2]='y';

........................


printf("Another? (y/n)");
scanf("%s", choice);

while(strncmp(choice,choice1,1)==0)
{ .......................

printf("Another? (y/n)");
scanf("%s", choice);
}

system("PAUSE");
return 0;



;

Cornedbee would probably break a candy dish over your head for this...

Errors in red

Code:

char choice[2], choice1[2];

choice1[2]='y'; /* Buffer overflow here. */

........................


printf("Another? (y/n)");
scanf("%s", choice); /* This isn't wrong, but  its not customarily how one would do it */

while(strncmp(choice,choice1,1)==0) /* Odd choice */
{ .......................

printf("Another? (y/n)");
scanf("%s", choice);
}

system("PAUSE");
return 0;



;

So lets see why I am breaking out the red. When you make an array your arrays are going to be filled with undefined data at first, and they are also going to start at index 0. So they go from 0 to n-1. So if you declare an array like this:

Example:

Code:

char array[50];

Then you can access from 0 to 49 (which is 50 - 1). If you are only comparing one char of string a and one char of string b, why not just directly compare them?

Example:

Code:

#include <stdio.h>
#include <ctype.h>

int main(void)
{
  char c;

  fputs("I am a program that doesn't do very much.\n", stdout);

  do
  {
    fputs("Do you wish to continue? (Y/N)", stdout);
    c = toupper(getchar());

    switch(c)
    {
       case 'Y':
         continue;
       case 'N':
         c = EOF;
         break;
       default:
         printf("I said Y/N not &#37;c! You will be punished for your insubordination!\n", c);
         while(1) { }
    }
  } while(c != EOF);

  return 0;
}

question. Is it a way to do a char to char compare.

so say that i have

scanf("%c", &a)

scanf("%c",&b)

Example:

Code:

#include <stdio.h>

int main(void)
{
  char a, b;

  scanf("&#37;c%c", &a, &b);

  if(a == b)
    puts("True");
  else
    puts("False");

  return 0;
}

see i had that down and it wasnt working. still trying here though

Because space is a perfectly good character that can be read in, unless you tell scanf not to by adding a space to the format string.

%c is one of the trickier to use scanf() flags. That is why you may have noticed that in my code I did not use it. Though mine would still suffer from the fact that it would accept ' ' as a the character the user typed.

You can always do something like:

Code:

char a[2];

scanf("%1s", a);

Which should be cool about not picking up leading spaces.

Code:

#include<stdio.h>
main()
{
char b;//variable for loop to be test
int a;//variable for choice
do
{
statement seq;//write your menus here!!
printf("\n\nenter choice:");//ask for the user to choose one of your menu
scanf("%d",&a);
switch(a)
{
case 1:
{
statement seq;
break;
}
case 2:
{
statement seq;
break;
}
defeult:
{
printf("\n\ninvalid choice!!!");//tells the user that they enter invalid choice from the menu
}
}//end of switch
printf("\nDo you want to try another?\ninput y if yes:");//ask the user if he/she wants to try another
scanf("%s",&b);//addressing variable to be test, i used %s because string is much better to use than the character
}while(b=='y'||b=='Y');
return 0;
}//end of main block!!