【C语言】赋值运算中的类型转换

#include<stdio.h>
int main()
{
    int a, b;
    double x = 1.54;
    char ch;
    a = x;
    x = ;
    b = 'a';
    ch = ;
    printf("a=%d\nx=%f\nb=%d\nch=\'%c\'\n",a,x,b,ch);
    return ;
}