/**
* 顺时针打印矩阵
* @author Q.Yuan
*
*/
public class ClockwisePrintMatrix {
public void printMatrix(int[][] a,int width,int height){
//起始打印坐标a[times][times],(0,0) (1,1) (2,2)...等
int times = 0;
while(times <= width - 1 - times && times <= height - 1 - times ){
//最右边的列号
int colNum = width - 1 - times;
//最下边的行号
int rowNum = height - 1 - times;
//第一步 打印上边的行(一定会打印)
for(int col = times;col <= colNum;col++){
System.out.print(a[times][col]+" ");
}
//第二步打印右边的列(两行以上才会打印)
if(rowNum - times > 0){
for(int row = times + 1;row <= rowNum;row++){
System.out.print(a[row][colNum]+" ");
}
}
//第三步打印下边的行（两列且两行以上才会打印）
if(colNum - times + 1 >
= 2 && rowNum - times + 1 >= 2){
for(int col = colNum - 1;col >= times;col--){
System.out.print(a[rowNum][col]+" ");
}
}
//第四步打印左边的行(三行且两列以上)
if(colNum - times + 1 >= 3 && rowNum - times + 1 >= 2){
for(int row = rowNum - 1;row >= times+1;row--){
System.out.print(a[row][times]+" ");
}
}
System.out.println();
times ++ ;
}
}
public static void main(String[] args) {
ClockwisePrintMatrix cpm = new ClockwisePrintMatrix();
int [][] a = {
{ -1, -2, 3, -4 },
{ -1, -2, 3, -4 },
{ -1, -2, 3, -4 }
};
cpm.printMatrix(a, a[0].length, a.length);
}
}