The Conditional operators

The conditional operators ? and : are sometimes called ternary operators since they take three arguments. In fact, they form a kind of foreshortened if-then-else. Their general form is:

expression1 ? expression2 : expression3;

What this expression says is: “if expression1 is true (that is, if its value is non-zero), then the value returned will be expression2, otherwise, the value returned will be expression3”. Let’s understand this with the help of a few examples:

1. int x, y;
   scanf("%d", &x);
   y = (x > 5 ? 3 : 4);
   

   This statement will store 3 in y if x is greater than 5, otherwise it will store 4 in y.

   The equivalent if statement will be:

   if (x > 5) {
     y = 3;
   } else {
     y = 4;
   }
   

2.  char a;
    int y;
    scanf("%c", &a);
    y = (a >= 65 && a <= 90 ? 1 : 0);
   

   Here 1 would be assigned to y if a >= 65 && a <= 90 evalutes to true, otherwise 0 would be assigned.

   The following points may be noted about the conditional operators:

   a. It is not necessary that the conditional operators should be used only on arithmetic statements. This is illustrated in the following examples:

   int i;
   scanf("%d", &i);
   (i == 1 ? printf("Amit\n") : printf("All and sundry\n"));
   

   char a = 'z';
   printf("%c", (a >= 'a' ? a : '!'));
   

   b. The conditional operators can be nested as shown below:

   int big, a, b, c;
   big = (a > b ? (a > c ? 3 : 4) : (b > c ? 6 : 8));
   

Contents