Question

C语言 warning C4700: local variable 'salary' used without having been initialized

本人是C语言初学者，
这个程序运行时发生了错误，没有error，但有个warning

#include <stdio.h>
void main(void)
{
double rate,tax,salary;
printf("请输入月薪：");
scanf("%f",salary);

if (salary<=850)
{ rate=0;
tax=rate*(salary-850);
printf("tax=% .2lf",tax);
}
else if(850<salary&&salary<=1350)
{ rate=0.05;
tax=rate*(salary-850);
printf("tax=% .2lf",tax);
}
else if(1350<salary&&salary<=2850)
{ rate=0.1;
tax=rate*(salary-850);
printf("tax=% .2lf",tax);
}
else if(2850<salary&&salary<=5850)
{ rate=0.15;
tax=rate*(salary-850);
printf("tax=% .2lf",tax);
}
else if(5850<salary)
{ rate=0.2;
tax=rate*(salary-850);
printf("tax=% .2lf",tax);
}

}

Answer 1

double rate,tax,salary = 0; //初始化一下
printf("请输入月薪：");
scanf("%f",salary); //这个错了，
改为：scanf("%lf",&salary);
double类型输入要用 lf

Answer 2

scanf("%f",salary);改为scanf("%lf",&salary);