使用for循环生成模式

Question

如何仅使用for循环生成此序列？

***+++------+++*** 

我试图做这样的，但它看起来不正确

String u =""; 
for(i=1;i<3;++i) 
{ 
    u = u + "***" + "+++" + "---"; 
} 

System.out.println(u); 

Answer 1

嗯，你可以这样做：

for (int i = 1; i < 2; ++i) { 
    System.out.println("***+++------+++***"); 
} 

但想必这不是你想要的。这个怎么样：

String symbols = "*+-"; 
for (int s = 0; s < symbols.length(); ++s) { 
    char c = s.charAt(s); 
    for (int i = 0; i < 3; ++i) { 
     System.out.print(c); 
    } 
} 
for (int s = symbols.length() - 1; s >= 0; --s) { 
    char c = s.charAt(s); 
    for (int i = 0; i < 3; ++i) { 
     System.out.print(c); 
    } 
} 
System.out.println(); 

要不然：

String symbols = "*+-"; 
int len = symbols.length(); 
StringBuilder output = new StringBuilder(); 
for (int s = 0; s < len; ++s) { 
    char c = s.charAt(s); 
    for (int i = 0; i < 3; ++i) { 
     output.append(c); 
    } 
} 
System.out.print(output); 
System.out.println(output.reverse()); 

甚至：

String symbols = "*+-"; 
int len = symbols.length(); 
StringBuilder prefix = new StringBuilder(); 
StringBuilder suffix = new StringBuilder(); 
for (int s = 0; s < len; ++s) { 
    char c1 = s.charAt(s); 
    char c2 = s.charAt(len - 1 - 1); 
    for (int i = 0; i < 3; ++i) { 
     prefix.append(c1); 
     suffix.append(c2); 
    } 
} 
System.out.print(prefix); 
System.out.println(suffix);