c - Switch statement not doing what I expect

Question

What is wrong with this code:

switch (n)
{
    case 0:   strcpy(resultString, "Zero");
    case 1:   strcpy(resultString, "One");
    case 2:   strcpy(resultString, "Two");
    case 3:   strcpy(resultString, "Three");
    case 4:   strcpy(resultString, "Four");
    case 5:   strcpy(resultString, "Five");
    case 6:   strcpy(resultString, "Six");
    case 7:   strcpy(resultString, "Seven");
    case 8:   strcpy(resultString, "Eight");
    case 9:   strcpy(resultString, "Nine");
}
printf("%s", resultString);

It always prints "Nine" no matter the value of n. What am I doing wrong??

Answer 1

You need a break statement at the end of each case. Otherwise control falls straight through to the next case.

Change your code to:

switch (n)
{
    case 0: strcpy(resultString, "Zero"); 
            break;
    case 1: strcpy(resultString, "One"); 
            break;
    case 2: strcpy(resultString, "Two"); 
            break;
    case 3: strcpy(resultString, "Three"); 
            break;
    case 4: strcpy(resultString, "Four"); 
            break;
    case 5: strcpy(resultString, "Five"); 
            break;
    case 6: strcpy(resultString, "Six"); 
            break;
    case 7: strcpy(resultString, "Seven"); 
            break;
    case 8: strcpy(resultString, "Eight"); 
            break;
    case 9: strcpy(resultString, "Nine"); 
            break;
}
printf("%s", resultString);

You can find the switch statement documented here or in any book on the C language.