各位大侠：
vc++6.0怎么输入下划线

#include<stdio.h>
 void main()
{
const int FREEING=0;
float temperature;
int cold-days;
int all-days=;
printf("Enter the list of daily low temperaturee.\n");
printf('Use celsius,and enter q to quit.\n');
while(scanf('%f',&temperature)==1)
{
all-days++;
if(temperature<FREEING)
cold-days++;
}
if(all-days!=0)
printf('%d days total;%.f%% were below freezing.\n'
                        alldays,100.0*(float)cold-days/all-days);
if(all-
days==0)
    printf('No data entered!\n');
    return 0;
    }