C Type Casting

Converting one datatype into another is known as type-casting or type conversion. There are two types of typecast supported by C:

1. Implicit Type Casting
2. Explicit Type Casting

Implicit Type Casting

In Implicit type casting a.k.a. automatic type conversion, the compiler automatically converts the data type when required. This is done to avoid loss of data during certain arithematic operations. However, the conversion may result in loss of the sign when converted from signed datatype to unsigned. The implicit type conversion follows the order provided below.

bool -> char -> short int -> int ->unsigned int -> long -> 
unsigned -> long long -> float -> double -> long double

Example Code

#include<stdio.h>
int main(void)
{
    int key = 3;
    char str[50];
    char ostr[50];
    int i = 0;

    printf("Insert plain Text\n");
    scanf("%s",&str);

    while(str[i] != '\0')
    {
        //Implicit type conversion
        ostr[i] = str[i] + key;
        i++;
    }
    ostr[i] = '\0';

    printf("Encrypted Text\n");
    printf("%s\n",ostr);

    return 0;
}

Output

Insert plain Text
ABC
Encrypted Text
DEF

Explicit Type Casting

Explicit type conversion is the process of forcefully casting a data type into another.

Syntax

(type) expression

#include<stdio.h>
int main(void)
{
    int x = 5;
    int y = 2;
    float z;

    //Explicit type conversion from int to float
    z = (float)x / (float)y;
    printf("Explicit Type Conversion: %d / %d = %f\n",x,y,z);
    
    z = x / y;
    printf("Without Type Conversion: %d / %d = %f\n",x,y,z);
    return 0;
}

Output

Explicit Type Conversion: 5 / 2 = 2.500000
Without Type Conversion: 5 / 2 = 2.000000