What are implicit and explicit type conversions in C language?

Converting one data type into another data type is called type conversions.

Implicit type conversion

The compiler provides implicit type conversions when operands are of different data types.
It is automatically done by the compiler by converting smaller data type into a larger data type.

int i,x;
float f;
double d;
long int l;

Here, the above expression finally evaluates to a ‘double’ value.

Following is an example for implicit type conversion −

int x;
for(x=97; x<=122; x++){
   printf("%c", x); /*Implicit casting from int to char %c*/
}

Explicit type conversion is done by the user by using (type) operator.
Before the conversion is performed, a runtime check is done to see if the destination type can hold the source value.

int a,c;
float b;
c = (int) a + b

Here, the resultant of ‘a+b’ is converted into ‘int’ explicitly and then assigned to ‘c’.

Following is an example for explicit type conversion −

int x;
for(x=97; x<=122; x++){
   printf("%c", (char)x); /*Explicit casting from int to char*/
}

Let us see the difference between the two types of conversions with examples −

#include<stdio.h>
main(){
   int i=40;
   float a;
   //Implicit conversion
   a=i;
   printf("implicit value:%f\n",a);
}

Implicit value:40.000000

#include<stdio.h>
main(){
   int i=40;
   short a;
   //Explicit conversion
   a=(short)i;
   printf("explicit value:%d\n",a);
}

Explicit value:40