How can I make a switch-case statement to not be case sensitive?
Say I made something like this:
#include <stdio.h>
char choice;
int main ()
{
char choice;
printf("Will you choose A,B, or C?\n>");
scanf(" %c", &choice);
switch(choice)
{
case 'A':
printf("The First Letter of the Alphabet");
break;
case 'B':
printf("The Second Letter of the Alphabet");
break;
case 'C':
printf("The Third Letter of the Alphabet");
break;
}
}
It would only respond to capital letters. How do I make it respond to lower case letters?
toupper in <ctype.h> converts a character to uppercase:
#include <stdio.h>
#include <ctype.h>
char choice;
int main ()
{
printf("Will you choose A,B, or C?\n>");
scanf(" %c", &choice);
switch(toupper(choice)) // Changed line
{
case 'A':
printf("The First Letter of the Alphabet");
break;
case 'B':
printf("The Second Letter of the Alphabet");
break;
case 'C':
printf("The Third Letter of the Alphabet");
break;
}
You simply need this :-
switch(choice)
{
case 'A':
case 'a':
printf("The First Letter of the Alphabet");
break;
case 'B':
case 'b':
printf("The Second Letter of the Alphabet");
break;
case 'C':
case 'c':
printf("The Third Letter of the Alphabet");
break;
}
and so on to continue your series.
Actually,what it does is that it bypasses(skims) upto bottom until it finds the first break statement matching the case thereby executing all the cases encountered in between!!!
Before the switch(), add:
choice = toupper(choice);
And if you haven't already got it, #include <ctype.h> to get the prototype.
You can give 2 cases one by one,
switch(choice)
{
case 'A':
case 'a':
printf("The First Letter of the Alphabet");
break;
case 'B':
case 'b':
printf("The Second Letter of the Alphabet");
break;
case 'C':
case 'c':
printf("The Third Letter of the Alphabet");
break;
}
Related
I’m new to C and currently doing a Jack ‘N Poy that requires the project to restart when the user prompt it like by answering y. However, I can’t seem to grasp its pattern. Have tried it on C++ and it worked but not on C. Can anyone help? I want the user to have the ability to play again after finishing the game.
Here is the code:
#include<stdio.h>
int main (){
char firstPlayer, secondPlayer, again;
do{
printf("Jack 'n Poy)\nEnter Player 1 input: ");
scanf("%c ", &firstPlayer);
printf("Enter Player 2 input: ");
scanf("%c", &secondPlayer);
switch (firstPlayer){
case 'x':
switch (secondPlayer){
case 'x':
printf("Draw");
break;
case 's':
printf("Player 2 wins");
break;
case 'p':
printf("Player 1 wins");
}
break;
case 's':
switch (secondPlayer){
case 'x':
printf("Player 1 wins");
break;
case 's':
printf("Draw");
break;
case 'p':
printf("Player 2 wins");
}
break;
case 'p':
switch (secondPlayer){
case 'x':
printf("Player 2 wins");
break;
case 's':
printf("Player 1 wins");
break;
case 'p':
printf("Draw");
}
break;
default:
printf("Invalid input");
}
printf("\nPlay again? (y/n)");
scanf("%c", &again);
}
while (again == 'y');
printf("Thank you for playing");
return 0;
}
Have also tried adding a substitute variable for the y and yes it does loop, but the loop skips the first question.
Your help are very much appreciated. Thank you very much!
You need to change the format to:
scanf(" %c", ...);
in all scanfs. Note the ' ' before %c
Your again is a string. You can use strcmp(expectedString,inputString) as the condition at while. You will need to include the string.h header file to be able to do this.
Alternatively, change again to char type, i.e. char again;
And then use %c in the last scanf, i.e. scanf("%c", &again);. You may face skipped character scenario if spaces or newlines are entered. In that case, refer to this answer for guidance.
here is a demo code for explaining what I'm actually looking for
I want to call a 'case' of "switch" - statement from somewhere else in the code in C Language.
Here is the source code:
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
char a;
int main()
{
printf("Enter a number: ");
scanf("%c", &a);
switch(a){
case 'a':
printf("This is for A & C");
break;
case 'b':
printf("This is for only B");
break;
case 'c':
// Here i want to call "case 'a':"
goto case 'a';
// how can a call another case here?
break;
default:
printf("Default");
break;
}
getch();
return 0;
}
Thanks is Advance :D
You need the so-called "fall-through" case:
So instead of this:
case 'a':
printf("This is for A & C");
break;
case 'b':
printf("This is for only B");
break;
case 'c':
// Here i want to call "case 'a':"
Write this:
case 'a':
case 'c':
printf("This is for A or C");
break;
case 'b':
printf("This is for only B");
break;
I'm working on a C code that will take an alphabetic phone number and convert into numbers. I'm stuck on the output. The output wil drop numbers needed. Such as 1-800-GATOR, will return 42867 but not 1-800-42867. This is what I have so far....
#include <ctype.h>
#include <stdio.h>
int main (void)
{
char ch;
int num_vowels = 0;
printf("Please Enter a phone number: ");
while ((ch = getchar()) != '\n')
{
switch (ch) {
case 'A': case 'B': case 'C':
putchar('2');
break;
}
switch (ch) {
case 'D': case 'E': case 'F':
putchar ('3');
break;
}
switch (ch) {
case 'G': case 'H': case 'I':
putchar ('4');
break;
}
switch (ch) {
case 'J': case 'K': case 'L':
putchar ('5');
break;
}
switch (ch) {
case 'M': case 'N': case 'O':
putchar ('6');
break;
}
switch (ch) {
case 'P': case 'Q': case 'R': case 'S':
putchar ('7');
break;
}
switch (ch) {
case 'T': case 'U': case 'V':
putchar ('8');
break;
}
switch (ch) {
case 'W': case 'X': case 'Y': case 'Z':
putchar ('9');
break;
}
printf("%c", num_vowels);
}
return 0;
}
Is it something that I'm missing in printf("%c", num_vowels);?
Any help is appricated!
You may have misunderstood the switch statement. While your usage does perform correctly, you only need one statement with multiple cases:
switch (ch) {
case 'A': case 'B': case 'C':
putchar('2');
break;
case 'D': case 'E': case 'F':
putchar('3');
break;
case 'G': case 'H': case 'I':
putchar('4');
break;
/* ... */
}
Note that nothing happens when the input doesn't match any of the cases. That's why only capital letters are transformed and sent to the output. One simple solution would be adding a default case. This way, when the input character is not any capital letter it is sent straight to output. Add this to the end of your switch:
switch(ch) {
case 'A': case 'B':
/* ... */
default:
putchar(ch);
break;
}
You could perform other checks as well, only printing certain characters for example.
As for printf("%c", num_vowels); there is nothing wrong with it, except that num_vowels is never used. So you should expect it to print a null character ('\0') after every character sent to output. I'm not sure about your intentions, but if it was a counter, you should increment the variable and print it only after reading input, outside the while loop.
#include <stdio.h>
#include <ctype.h>
int
main(int argc, char **argv)
{
char ch;
int num_letters = 0;
printf("Please Enter a phone number: ");
while ((ch = getchar()) != '\n')
{
if (isupper(ch)) num_letters++;
switch (ch) {
case 'A': case 'B': case 'C':
putchar('2');
break;
case 'D': case 'E': case 'F':
putchar('3');
break;
case 'G': case 'H': case 'I':
putchar('4');
break;
case 'J': case 'K': case 'L':
putchar('5');
break;
case 'M': case 'N': case 'O':
putchar('6');
break;
case 'P': case 'Q': case 'R': case 'S':
putchar('7');
break;
case 'T': case 'U': case 'V':
putchar('8');
break;
case 'W': case 'X': case 'Y': case 'Z':
putchar('9');
break;
default:
putchar(ch);
break;
}
}
printf("\n-- %d alphabetic letters used.\n", num_letters);
return 0;
}
Use int ch instead of char ch because getchar returns int. You should compare ch with EOF and handle that case.
Your code doesn't handle the case where a user enters a lower-case letter (e.g. 'a' instead of 'A'). You can correct this by using ch = toupper(ch);
You don't need to repeat each switch() statement.
num_vowels isn't being modified.
printf("%c", num_vowels) should be printf("%d") as num_vowels represents a human-readable number, not a character value.
printf(... should be after your while loop, not inside it.
You cannot use getchar and putchar to supplant user-input (i.e. disable local input echo), that requires platform-specific APIs. I recommend prompting the user to input a whole line of text first (into a char*), then process the line of text.
I guess you are wrong with how you are processing the input.
When you are taking input from the user i.e. 1-800-GATOR, you should skip the first 6 characters i.e "1-800-" and then start your switch case loop.
Also, the variable num_vowels is unchanged since you defined it till you print it. Why are you using it?
The code that will work for your statement will be:
#include <stdio.h>
int main (void)
{
char ch;
//int num_vowels = 0;
printf("Please Enter a phone number: ");
while ((ch = getchar()) != '\n')
{
switch (ch) {
case 'A': case 'B': case 'C':
putchar('2');
break;
case 'D': case 'E': case 'F':
putchar ('3');
break;
case 'G': case 'H': case 'I':
putchar ('4');
break;
case 'J': case 'K': case 'L':
putchar ('5');
break;
case 'M': case 'N': case 'O':
putchar ('6');
break;
case 'P': case 'Q': case 'R': case 'S':
putchar ('7');
break;
case 'T': case 'U': case 'V':
putchar ('8');
break;
case 'W': case 'X': case 'Y': case 'Z':
putchar ('9');
break;
}
}
printf("\n");
return 0;
}
I am a totally newbie about C programming. so my program is very long, sorry.
my professor wants to have a number system- binary to decimal, decimal to binary, octal to decimal, hexadecimal to binary. he also want to have a loop( if he wants to exit press [E], if not then press any key). Now i'm having a problem with this hexadecimal because it keeps saying " type mismatch in redeclaration" and i don't know now how to solve this problem.
so heres my not yet finished program because of "hexadecimal" problem. help me with this error. don't mind the octal to decimal, I am currently programming it :)
#include<stdio.h>
#include<conio.h>
#include<math.h>
#define MAX 1000
long num, decimal(long), octal(long), binary(long),j;
char hexadecimal(char), k[MAX];
main()
{
char choice;
clrscr();
printf("[B]inary to Decimal\n");
printf("[D]ecimal to Binary\n");
printf("[O]ctal to Decimal\n");
printf("[H]exadecimal to Binary\n");
printf("[E]xit\n");
printf(" Enter your choice....");
choice=getche();
switch(choice)
{
case 'b':
case 'B': binary(j); break;
case 'd':
case 'D': decimal(num); break;
case 'o':
case 'O':
case 'h':
case 'H': hexadecimal(k[MAX]); break;
case 'e':
case 'E': return 0;
default: printf("\n Invalid choice.... press any key to REPEAT");
getch();
main();
}
printf("\nDo you want to [E]xit?");
choice=getch();
switch(choice)
{
case 'e':
case 'E': printf("\nInvalid choice... press any key to repeat");
getch();
main();
}
getch();
return 0;
}
long binary(long j)
{
long binary_val,decimal_val=0, base=1, rem;
printf("Enter a binary number( 1s & 0s): ");
scanf("%ld",&j);
binary_val=j;
while(j>0)
{
rem=j % 10;
decimal_val=decimal_val + rem * base;
j= j/ 10;
base=base * 2;
}
printf(" The Binary Number is %ld\n",binary_val);
printf(" Its decimal equivalent is = %d\n",decimal_val);
}
long decimal(long num)
{
long decimal_num, remainder, base=1, binary=0;
printf(" \nEnter a decimal integer: ");
scanf("%ld",&num);
decimal_num=num;
while(num>0)
{
remainder= num % 2;
binary=binary + remainder * base;
num=num/2;
base= base * 10;
}
printf(" Input number is %d\n",decimal_num);
printf(" Its binary equivalent is = %ld",binary);
}
char hexadecimal(char k[MAX])
{
long int i=0;
clrscr();
printf(" Enter any Hexadecimal number: ");
scanf("%s",&k);
printf("\n Equivalent binary value: ");
while(k[i])
{
switch(k[i])
{
case '0': printf("0000"); break;
case '1': printf("0001"); break;
case '2': printf("0010"); break;
case '3': printf("0011"); break;
case '4': printf("0100"); break;
case '5': printf("0101"); break;
case '6': printf("0110"); break;
case '7': printf("0111"); break;
case '8': printf("1000"); break;
case '9': printf("1001"); break;
case 'a':
case 'A': printf("1010"); break;
case 'b':
case 'B': printf("1011"); break;
case 'c':
case 'C': printf("1100"); break;
case 'd':
case 'D': printf("1101"); break;
case 'e':
case 'E': printf("1110"); break;
case 'f':
case 'F': printf("1111"); break;
default: printf("\n Invalid hexadecimal digit %c",k[i]); return 0;
}
i++;
}
}
The error you are getting type mismatch in redeclaration of hexadecimalis a result of the difference between the function you prototyped and implemented.
Your prototype is:
char hexadecimal(char), k[MAX];
This line prototypes a function hexadecimal that returns a char and takes a char as an argument AND this line also declares a global char array k of size MAX.
Your actual function is:
char hexadecimal(char k[MAX])
This function is a function that returns a char, but instead of taking a char like your prototype it instead takes a char array of size MAX. As you can see the prototyped function and the function itself are not the same. By making the functions exactly the same you will fix your issue.
To be honest, you don't need to pass anything into that function nor make a global char array as you can locally hold the array based on your code. The only other time you use the array you just pass it to this function which means it is better of as a local to that function anyway. So, you can simply do this:
char hexadecimal(void)
{
char k[MAX]
//same code below...
Now the function takes no arguments and k is still declared in the function, but is local instead of global. The prototype for this function would simply be:
char hexadecimal(void);
although default part mustn't run,
it runs al case, I thanks for all helps at now, what should i do? This code all runs i writes on screen default case.
do
{
scanf("%c",&choice);
switch(choice)
{
case 'T':
printf("Enter edges of Triangle1\n");
scanf("%d%d",&edge1,&edge2);
Triangle1(edge1,edge2);
break;
case 't':
printf("Enter edges of Triangle1\n");
scanf("%d%d",&edge1,&edge2);
Triangle2(edge1,edge2);
break;
case 'R':
printf("Enter edges of square\n");
scanf("%d%d",&edge1,&edge2);
Rectangle(edge1,edge2);
break;
case 'S':
printf("Enter one edge of square\n");
scanf("%d",&edge);
Square(edge);
break;
case 'C':
printf("Enter radius of circile\n");
scanf("%d",&radius);
Circle(radius);
break;
default:
printf("Wrong input\n");
break;
}//end of switch
printf("\n");
}while(choice!='e');
The newline gets passed as well as input. Try calling "getc(stdin)" after the first scanf() and it should work :)
Check out for example: http://home.datacomm.ch/t_wolf/tw/c/getting_input.html#newline