1 //1.输出9*9 口诀. 9行9列, i控制行, j控制列 2 for (int i = 1; i < 10; i++) { 3 for (int j = 1; j <= i; j++) { 4 int result = j * i; 5 printf("%d * %d = %-3d", i, j, result);//其中-3d的作用是输出的时候能对齐; 6 } 7 printf(" ");//每一行换行 8 } 9 10 11 12 程序输出1 * 1 = 1 13 2 * 1 = 2 2 * 2 = 4 14 3 * 1 = 3 3 * 2 = 6 3 * 3 = 9 15 4 * 1 = 4 4 * 2 = 8 4 * 3 = 12 4 * 4 = 16 16 5 * 1 = 5 5 * 2 = 10 5 * 3 = 15 5 * 4 = 20 5 * 5 = 25 17 6 * 1 = 6 6 * 2 = 12 6 * 3 = 18 6 * 4 = 24 6 * 5 = 30 6 * 6 = 36 18 7 * 1 = 7 7 * 2 = 14 7 * 3 = 21 7 * 4 = 28 7 * 5 = 35 7 * 6 = 42 7 * 7 = 49 19 8 * 1 = 8 8 * 2 = 16 8 * 3 = 24 8 * 4 = 32 8 * 5 = 40 8 * 6 = 48 8 * 7 = 56 8 * 8 = 64 20 9 * 1 = 9 9 * 2 = 18 9 * 3 = 27 9 * 4 = 36 9 * 5 = 45 9 * 6 = 54 9 * 7 = 63 9 * 8 = 72 9 * 9 = 81