C Language Tutorials by Ghulam Murtaza Dahar - HTML preview

Explanation

Here, the operators +, - and * performed normally as you expected. In normal calculation, 9/4 equals to 2.25. But, the output is 2 in this program. It is because, a and b are both integers. So, the output is also integer and the compiler neglects the term after decimal point and shows answer 2 instead of 2.25. And, finally a%b is 1,i.e. ,when a=9 is divided by b=4, remainder is 1.

Suppose a=5.0, b=2.0, c=5 and d=2

In C programming,

a/b=2.5

a/d=2.5

c/b=2.5

c/d=2

Note: % operator can only be used with integers.

Increment and decrement operators

In C, ++ and -- are called increment and decrement operators respectively. Both of these operators are unary operators, i.e, used on single operand. ++ adds 1 to operand and -- subtracts 1 to operand respectively. For example:

Let a=5 and b=10

a++; //a becomes 6

a--; //a becomes 5

++a; //a becomes 6

--a; //a becomes 5

Difference between ++ and -- operator as postfix and prefix

When i++ is used as prefix(like: ++var), ++var will increment the value of var and then return it but, if ++ is used as postfix(like: var++), operator will return the value of operand first and then only increment it. This can be demonstrated by an example:

#include <stdio.h>

int main(){

int c=2,d=2;

printf("%d\n",c++); //this statement displays 2 then, only c incremented by 1 to 3.

printf("%d",++c); //this statement increments 1 to c then, only c is displayed.

return 0;

}