Implicit type conversion in C++ | Automatic type conversion in C++

Implicit conversion in C++ is also called automatic type conversion in C++. It is the process in which output of arithmetic expression automatically gets converted into a specific data type.

Basic rule of Automatic type conversion is, output of arithmetic expression will be of that data type that has the highest number of bytes and range.

Example:

In an arithmetic expression if one value is of short type and other is of int type, the output is of int type because int type value more size and better range of values as compared to short data type.

Rules of implicit conversion

Data type of first value	Data type of Second Value	Data type of Result
short	short	short
short	int	int
short	long	long
short	float	float
short	double	double
short	long double	long double
short	char	short
int	int	int
int	long	long
int	float	float
int	double	double
int	long double	long double
int	char	int
long	long	long
long	float	float
long	double	double
long	long double	long double
long	char	long
float	float	float
float	double	double
float	long double	long double
float	char	float
double	double	double
double	long double	long double
double	char	double
long double	long double	long double
long double	char	long double
char	char	char

 //Program to demonstrate Implicit conversion

#include<iostream> 
using namespace std;
int main()
{
  int n;
  double m;
  n=10/3;    //Line 7
  cout<<"\n10/3="<<n;  
  m=10/3;         //Line 9
  cout<<"\n10/3="<<m; 
  n=10.0/3;         //Line 11
  cout<<"\n10.0/3="<<n;  
  m=10.0/3;         //Line 13
  cout<<"\n10.0/3="<<n; 
  return 0;
}

Output:

10/3=3
10/3=3.000000
10.0/3=3
10.0/3=3.333333

** In line 7 of above program, 10 and 3 are int type values so result of 10/3 is of int type i.e. 3 which is assigned to variable n which is of int type. So n  contains 3.

In line 9, 10 and 3 are int type values so result of 10/3 is of int type i.e. 3 which is assigned to variable m which is of double type. So m  contains 3.000000.

In line 11, 10.0 is double type value  and 3 is an  int type value so result of 10.0/3 is of double type i.e. 3.333333 which is assigned to variable n which is of int type. So n  contains 3.

In line 13, 10.0 is double type value  and 3 is an  int type value so result of 10.0/3 is of double type i.e. 3.333333 which is assigned to variable m which is of double type. So m  contains 3.333333.

Lesson tags: Automatic type conversion in C++, implicit conversion in c

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