Question

When is a switch statement better than multiple if statements in C Language?

Answer 1

A switch statement is generally best to use when you have more than two conditional expressions based on a single variable of numeric type. For instance, rather than the code

if (x == 1)
     printf("x is equal to one.\n");
else if (x == 2)
     printf("x is equal to two.\n");
else if (x == 3)
     printf("x is equal to three.\n");
else
     printf("x is not equal to one, two, or three.\n");

the following code is easier to read and maintain:

switch (x)
{
     case 1:   printf("x is equal to one.\n");
                    break;
     case 2:   printf("x is equal to two.\n");
                    break;
     case 3:   printf("x is equal to three.\n");
                    break;
     default:  printf("x is not equal to one, two, or three.\n");
                    break;
}

Notice that for this method to work, the conditional expression must be based on a variable of numeric type in order to use the switch statement. Also, the conditional expression must be based on a single variable. For instance, even though the following if statement contains more than two conditions, it is not a candidate for using a switch statement because it is based on string comparisons and not numeric comparisons:

char* name = "Lupto";
if (!stricmp(name, "Isaac"))
     printf("Your name means 'Laughter'.\n");
else if (!stricmp(name, "Amy"))
     printf("Your name means 'Beloved'.\n ");
else if (!stricmp(name, "Lloyd"))
     printf("Your name means 'Mysterious'.\n ");
else
     printf("I haven't a clue as to what your name means.\n");

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