casting in c

1#include <stdio.h>
2
3main() {
4
5   int sum = 17, count = 5;
6   double mean;
7
8   mean = (double) sum / count;
9   printf("Value of mean : %f\n", mean );
10}
11

1#include <stdio.h>
2#include <stdlib.h>
3int main(){
4  int x = 7, y = 5;
5  float z;
6  z = (float)x / (float)y;   /*Here the value of z is 1.400000*/
7  return 0;
8}

1(new_type) name_var;