switch statements in while loops - c

Question

I am in a chapter for control structures, i threw myself a while n case challenge but i can't seem to get it working, any heads up ?, i know my code is a bit dirty or alot dirty :D anyway the code is about asking a user for input on a color name then prints a corresponding color code, after that it asks if you want to continue if yes it continues if not it terminates.
#include <stdio.h>
main ()
{
char color[20];
char answer;
printf("Enter the color name: ");
scanf("%s", &color);
while (1) {
switch("color")
{
case "red":
printf("#FF0000\n");
break;
case "green":
printf("#00FF00\n");
break;
default:
printf("FFFFFF\n");
}
printf("Do you want to do that again(y/n): ");
scanf("%c", &answer);
if (answer == "y")
{
printf("Enter the color code: ");
scanf("%s",&color);
}
else
{
printf("Quiting.......\n");
break;
}
}
return 0;
}

Answer 1

There's more than one problem, but here's a few:
You're not comparing strings the right way. In C you can't use == to compare strings, you have to use strcmp (or strncmp).
You can't switch on a string in C. So you might want to replace the switch with if-else:
if (!strcmp(color, "red"))
/* ... */
else if (!strcmp(color, "green"))
/* ... */
else
/* "default" */
You're mixing different scanf strategies:
scanf("%s",&color); leaves \n in the input buffer
scanf("%c", &answer); reads that newline and stores it in answer
Basically the only good advice is: keep studying. You're not ready for this "challenge" yet.

Answer 2

Your switch statement always goes to default:. This is because you have the litaral "color" instead of the variable color.
You want
switch(color) {
but as pointed by others, that won't work either, because C switch doesn't allow strings.

Answer 3

You want to write:
switch (color)
{
...
}
but even that won't work since you need an integer expression; C does not handle string comparisons natively.
So, you'll either have to map the colour strings to integers, or forego a switch and use an `if / else if / else' chain:
if (strcmp(color, "red") == 0)
printf("#FF0000\n");
else if (strcmp(color, "green") == 0)
printf("#00FF00\n");
else
printf("FFFFFF\n");

Answer 4

To answer your question, you have to remember what is a string literal in C.
They are pointers to character arrays with string data embedded in the code by the compiler.
So, firstly, your switch statement uses a constant (address of "color" string) as a control variable.
Secondly, each case branch contains a meaningless address of a string as a label.
To emulate switch on strings in C, you have to use a sequence of if-else if with strcmp in conditions.