用obj-c写一个冒泡排序
for（int i = 0, i < arr.count - 1,i++){
for (int j = 0,j < arr.count - 1 - i;j++){
int a = [[arr objectAtIndex:j]intValue];
int b=[[arr objectAtIndex:j+1]intValue];
if(a < b){
[arr replaceObjectAtIndex:j withObject:[NSString stringWithFormat:@“%d”,b]];
[arr replaceObjectAtIndex:j+1 withObject:[NSString stringWithFormat:@“%d”,a];
}
}
}
