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Programs coded with short-hand operators can run several milliseconds faster. Same as increment and decrement operators. They are — (minus minus) and ++ (plus plus). The following example shows the usage of these two operators:

x = y + z++; // z is incremented by one after x was calculated
x = y + --z; // Decrement z by one first, then calculate x

In the above example, if y = 2 and z = 4:

x = 2 + 4++ => x = 6 (z has become 5, x doesn’t change since it’s already calculated)
x = 2 + –4 => x = 2 + 3 => x = 5 (z first decremented to 3, and then calculates x)

As you can see, the position of the operator is very important.

Here is the sample code for these operators:

/*
 * inDecrement.c
 *
 * Program to illustrate the use of the increment
 * and decrement operators
 *
 * by Mark Virtue, 2001.
 *
*/

#include <stdio.h>

main() {
 int x, y, z = 1;

 y = 5;
 x = 6;

 puts(""); // Prints out a new line
 printf("Before: x = %d, y = %d, z = %dn", x, y, z);

 z = x++ + ++y; // First y is incremented to 6, and then z gets calculated to 12. Lastly, x is incremented to 7

 puts("");
 puts("z = x++ + ++y");
 printf("After: x = %d, y = %d, z = %dn", x, y, z);

 puts("");
 printf("Before: x = %d, y = %d, z = %dn", x, y, z);

 z = x++ - --y; // Same format as above

 puts("");
 puts("z = x++ - --y");
 printf("After: x = %d, y = %d, z = %dn", x, y, z);

 fflush(stdin);
 getchar();
}

And here is the output for the above code:

Output for the above sample code. Click the image to enlarge.

If you have any question regarding the increment and decrement operators, leave a comment below.

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