#include <stdio.h>int main(void) { int i,j;for(j=1; j < 10; j ++)for(i = 1;i < 10; i ++){if(i < j){if((i == 2) && (3 == j || 4 == j))printf("%d * %d = %d \t",i, j, i*j);//调整数字布局，使得数字输出对齐elseprintf("%d * %d = %d\t",i, j, i*j);}if(i == j) //一共9行数字相乘，到每行结尾处进行换行printf("%d * %d = %d\n",i, j, i*j);}return 0;}
运行输出如下：
1 * 1 = 1
1 * 2 = 2 2 * 2 = 4
1 * 3 = 3 2 * 3 = 6 3 * 3 = 9
1 * 4 = 4 2 * 4 = 8 3 * 4 = 12 4 * 4 = 16
1 * 5 = 5 2 * 5 = 10 3 * 5 = 15 4 * 5 = 20 5 * 5 = 25
1 * 6 = 6 2 * 6 = 12 3 * 6 = 18 4 * 6 = 24 5 * 6 = 30 6 * 6 = 36
1 * 7 = 7 2 * 7 = 14 3 * 7 = 21 4 * 7 = 28 5 * 7 = 35 6 * 7 = 42 7 * 7 = 49
1 * 8 = 8 2 * 8 = 16 3 * 8 = 24 4 * 8 = 32 5 * 8 = 40 6 * 8 = 48 7 * 8 = 56 8 * 8 = 64
1 * 9 = 9 2 * 9 = 18 3 * 9 = 27 4 * 9 = 36 5 * 9 = 45 6 * 9 = 54 7 * 9 = 63 8 * 9 = 72 9 * 9 = 81
j为行，i为列，j每行递增1，i从1变化到j，当i等于j时，进行换行，2*3 = 6 、2*4=8之后加了一个空格，保持
第三列对齐。
