1. post-increment and pre-increment 的区别

来源：http://www.c4learn.com/c-programming/c-increment-operator/

#include<stdio.h>

void main()

{

int a,b,x=,y=;

a = x++;

b = ++y;

printf("Value of a : %d",a);

printf("Value of b : %d",b);

}

Different Types of Increment Operation

In C Programming we have two types of increment operator i.e Pre-Increment and Post-Increment Operator.

A. Pre Increment Operator

Pre-increment operator is used to increment the value of variable before using in the expression. In the Pre-Increment value is first incremented and then used inside the expression.

b = ++y;

In this example suppose the value of variable ‘y’ is 5 then value of variable ‘b’ will be 6 because the value of ‘y’ gets modified before using it in a expression.

B. Post Increment Operator

Post-increment operator is used to increment the value of variable as soon as after executing expression completely in which post increment is used. In the Post-Increment value is first used in a expression and then incremented.

b = x++;

In this example suppose the value of variable ‘x’ is 5 then value of variable ‘b’ will be 5 because old value of ‘x’ is used.