[swift]学习之基础语法

1，题目：判断101-200之间有多少个素数，并输出所有素数。

for (var i=101; i<200; i++){
    var m=2
    for( m; m<i; m++){
        if(i%m==0 ){
            break
        }
    }
    if(m>=i){
        print(i)
    }
}

2，题目：假设有一个学习成绩的数组，利用条件运算符的嵌套来完成此题：学习成绩> =90分的同学用A表示，60-89分之间的用B表示，60分以下的用C表示。

var chengji=[92,78,56]
for (index, value) in chengji.enumerate(){
    if(value<60){
        print("C")
    }else{
        if(value>90){
            print("A")
        }else{
        print("B")
        }
    }
}
以上是数组表示成绩，下面是字典

var chengji2=[String:String]()
var chengji=["tom":92,"suda":78,"penny":56]
for (name,score) in chengji{
    if (score<60){
        chengji2[name] = "C"
    }else{
        if(score>90){
        chengji2[name] = "A"
        }else{
        chengji2[name] = "B"
        }
    }
    print("(name):(score)")
}
print(chengji2)

3，题目：输入某年某月某日，判断这一天是这一年的第几天？

var year = 2015
var month = 6
var day = 23
var Feb:Int
var days:Int

if(year%4 == 0||(year%4==0 && year%100 != 0)){
    Feb = 29
}else{
    Feb = 28
}
switch month {
case 1:
    days = 0
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 2:
    days = 31
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 3:
    days = 31+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 4:
    days = 62+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 5:
    days = 92+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 6:
    days = 123+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 7:
    days = 153+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 8:
    days = 184+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 9:
    days = 215+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 10:
    days = 245+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 11:
    days = 276+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
case 12:
    days = 306+Feb
    print("(year)年(month)月(day)日是(year)年的第(day+days)天")
default:
    print("输入有误")
}