打印N字形

根据输入的内容打印
 //比如 [obj printString:@"12345"];
 
 1   1
 2  22
 3 3 3
 44  4
 5   5
 
 */

- (void)printString:(NSString *)string{
    NSMutableString *muStr = [[NSMutableString alloc]init];
    NSInteger length = string.length;
    for (int i = 0; i < length; i++) {
        for (int j = 0; j < length; j++) {
            if (j == 0) {//第一列
                [muStr appendFormat:@"%c",[string characterAtIndex:i]];
            }else if (j + i == length -1){//这是副对角线的表示方法
        &nbs