求一个判断闰年的代码

if(month==2){
if( year % 4 == 0 && ( year % 100 != 0 || year % 400 == 0)){
day = 29;
}else{
day = 28
}
}else if (month==4 || month==6 || month==9 || month==11){
day = 30;
}else{
day = 31;
}

单纯判断年份是否为闰年用这句就可以了
if( year % 4 == 0 && ( year % 100 != 0 || year % 400 == 0)){
year = "闰年";
}

我用c语言给你写了
main()
{int yy;
printf("Inter a year:\n");
scanf("%d",&yy);
if(yy%100==0&&yy%400==0||yy%100!=0&&yy%4==0)
printf("This is a leap year\n");
else
printf("This is not a leap year\n");
}

4