5.1
5.2
5.3if
5.4switch
5.5
5.1.1
C6
():
()
=()
()
=()
():
= = ()
!=()
5.1
1.
2.01
3.
1
2
cab c(ab)
ab==c (ab)==c
a=bc a=(bc) 5.1
5.2
(1) &&(AND)
(2) || ()
(3) ! (NT)
“&&” ||” ()
!” ()
1.01
2.
5>3&&8<4-!0
(5>3)&&(8<4-!0)
(1) a && b && c
(2) a||b||c
… …
…
C
if
5.3 if
if()
5.3.1 if
Cif
1,if
N
Y
2,if
1 2
Y N
1
2
if(a>60)
printf(“\n”
else
printf(“\n”);
a>60Y N
3,i f
……
1
N
1
Y 2
n
Y
Y
2 3 n
N
N
if(number>500) cost=0.15;
else if(number>300) cost=0.10;
else if(number>100) cost=0.075;
else if(number>50) cost=0.05;
else cost=0;
if
(1) ifif
if
if(3) printf(“k )
if(?a?)printf(“d” a?)
(2)
(3)
(4) else
(5)if{ }{ }
,”
,”
if
if
if( 1 11
else 12
else
if (2 21
else 22
0101112
0202122
if if
ifelse,,:
if( )
{ if () 1}
else
2
{ }if,elseif
ifelseelseif
int I=1;
if(I<=0) printf("****\n")
else printf("%%%%\n");
main()
{ int a=5,b=4,c=3,d=2;
if(a>b>c)
printf("%d\n",d);
else if((c-1>=d)==1)
printf("%d\n",d+1);
else
printf("%d\n",d+2);
}
( ),3
main()
{ int x;
scanf("%d",&x);
if(x--<5)
printf("%d",x);
else
printf("%d",x++);
}
5( )
:4
main()
{
int a=3,b=4,c=5,d=2;
if(a>b)
if(b>c)
printf("%d",d++ +1);
else
printf("%d",++d +1);
printf("%d\n",d);
}
( )
:2
A if(a)
printf("%d\n",x);
else
printf("%d\n",y)
B if(a==0)
printf("%d\n",y);
else
printf("%d\n",x)
C if (a!=0)
printf("%d\n",x);
else
printf("%d\n",y)
D if(a==0)
printf("%d\n",x);
else
printf("%d\n",y)26
123
123
if(a>b) max=a;
else max=b;
max=(a>b)?a:b;
cSwitch
switch()
case11
case22
…
casenn
default n1
switch
,=i,i,n+1
,default
Switch
Switch(grade)
case'a' printf("85100n")
case'b' printf("7084n")
case'c' printf("6069n")
case d' printf("60n")
default printf("errorn")
2,case
1,int,char
3,case default
a
85100
7084
6069
60
error
c
6069
60
error
caseSwitchSwitchbreakSwitch
Switch(grade)
case'a' printf("85100n")break
case'b' printf("7084n")break
case'c' printf("6069n")break
case d' printf("60n")break
default printf("errorn")
(default)break grade b? 7084”5.12
casecase
(3) case
…
case'a'
case'b'
case'c' printf("60n")break
…
grade a? b? c?
main( )
{ int x=1,a=0,b=0;
switch(x){
case 0,b++;
case 1,a++;
case 2,a++;b++;
}
printf(“a=%d,b=%d\n”,a,b);
}
A a=2,b=1
B a=1,b=1
C a=1,b=0
D a=2,b=2
main()
{ int i;
for(i=0;i<3;i++)
switch(i)
{
case 0:printf("%d",i);
case 2:printf("%d",i);
default:printf("%d",i);
}
}
A 22111
B 21021
C 000122
D 00012