Cast Operator

Performs an explicit conversion into the given type from the value resulting from evaluating the given expression.

int x = 3;
int y = 4;
printf("%f\n", (double)x / y); /* Outputs "0.750000". */

Here the value of x is converted to a double, the division promotes the value of y to double, too, and the result of the division, a double is passed to printf for printing.