截断如何工作以及整数除法与浮点除法的区别

#include <stdio.h>
int main(void)
{
    printf("integer division:  5/4   is %d /n", 5/4);
    printf("integer division:  6/3   is %d /n", 6/3);
    printf("integer division:  7/4   is %d /n", 7/4);
    printf("floating division: 7./4. is %1.2f /n", 7./4.);
    printf("mixed division:    7./4  is %1.2f /n", 7./4);

    return 0;
}