1.
2.
(,,)
12 1234U 256L O46 OX123
(,)
12.5 12e3
( )
‘A’
()
int 2 %d
float 4 %f
char 1 %c
()
3.
:
1
,
int a,b,c;
a=3;b=3;c=3; /* a=b=c=3 */
2
1.
2.
double float
long
int char
1.:
(+)(-)(*)(/)(%)(++)(--)
(=)(+=,-=,*=,/=,%=)
(>)(<)(==) (>=)(<=)(!=)
(&&)(||)(!)
1?2,3
,1 2,….,n
( )
++ -- !
putchar();
#include <stdio.h>
getchar();
();
printf
(,);
scanf (,);
5.
C()
(V)
5.
()
main()
{float a,b,c,aver;
printf(“Please input a,b,c:”)
scanf(“%f,%f,%f”,&a,&b,&c);
aver=1.0/3*(a+b+c);
printf(“%.2f\n”,aver);
}
5.
()
main()
{float a,b,s,l;
printf(“Please input a,b:\n”)
scanf(“%f,%f”,&a,&b);
s=a*b;
l=(a+b)*2;
printf(“%.2f,%.2f\n”,s,l);
}