作业 3 利用分支与循环结构解决问题

2

#include<stdio.h>
int main(void)
{

int count,i,n;
double grade,total;
printf("Enter n:");
scanf("%d",&n);
total=0;
count=0;
for(i=1;i<=n;i++){

printf("Enter grade#%d:",i);
scanf("%lf",&grade);
total=total+grade;
if(grade>=60){

count++;
}
}
printf("Grade average=%.2f\n",total/n);
printf("Number of success=%d\n",count);
return 0;
}



3.

#include<stdio.h>
int main(void)
{
int letter,digit,blank,other;
char ch;
int i;
letter=digit=blank=other=0;
printf("Enter 15 characters:");
for(i=1;i<=15;i++){
ch=getwchar();
if((ch>='a'&&ch<='z')||(ch>='A'&&ch<='Z'))
letter++;
else if(ch>='0'&&ch<='9')
digit++;
else if((ch='\n')||(ch=' '))
blank++;
else
other++;

}
printf("letter=%d,digit=%d,blank=%d,other=%d\n",letter,digit,blank,other);
return 0;
}



4..

#include<stdio.h>
int main(void)
{
int year;
printf("Enter The year:");
scanf("%d",&year);
while(year!=-1){
if((year%4==0&&year%100!=0)||(year%400==0)){
printf("The year is 闰年\n");
printf("Enter The year:");
scanf("%d",&year);
}
else{
printf("The year is not 闰年\n");
printf("Enter The year:");
scanf("%d",&year);
}
}
return 0;
}



5.

#include<stdio.h>
int main(void)
{
char ch;
printf("Enter the level(A B C D E):");
ch=getchar();
switch(ch){
case'A':printf("The level is 90~100\n");break;
case'B':printf("The level is 80~89\n");break;
case'C':printf("The level is 70~79\n");break;
case'D':printf("The level is 60~69\n");break;
case'E':printf("The level is 0~59\n");break;
}
return 0;
}



6.

#include<stdio.h>
int main(void)
{
int choice,i;
double price;
for(i=1;i<=5;i++){
printf("[1]Select apples\n");
printf("[2]Select pears\n");
printf("[3]Select oranges\n");
printf("[4]Select grapes\n");
printf("[0]Select exit\n");
printf("Enter choice:");
scanf("%d",&choice);
if(choice==0)
break;
switch(choice){
case 1:price=3.00;break;
case 2:price=2.50;break;
case 3:price=4.10;break;
case 4:price=10.20;break;
default:price=0.00;break;
}
printf("price=%0.2f\n",price);
}
return 0;
}