c how to program 习题16

运行结果：

C语言代码：

/* c how to program 习题4.16
** 打印三角形 */
#include <stdio.h>
#include <math.h>
// function main begins program execution
int main( void )
{
    //定义x为*,y为换行,z为空格
    int x, y, z;

    //(A)
    for(y = 1; y <= 10; ++y){
        //打印*
        for(x = 0; x < y; x++){
            printf("*");
        }
        //打印换行
        printf("\n");
    }
    puts("");

    //(B)
    for(y = 10; y > 0; y--){
        //打印*
        for(x = 0; x < y; x++){
            printf("*");
        }
        //打印换行
        printf("\n");
    }
    puts("");

    //(C)
    for(y = 0; y < 10; ++y){
        //打印空格
        for(z = 0; z < y; z++){
            printf(" ");
        }
        //打印*
        for(x = 10; x > y; x--){
            printf("*");
        }
        //打印换行
        printf("\n");
    }
    puts("");

    //(D)
    for(y = 0; y < 10; ++y){
        //打印空格
        for(z = 9; z > y; z--){
            printf(" ");
        }
        //打印*
        for(x = 0; x <= y; x++){
            printf("*");
        }
        //打印换行
        printf("\n");
    }
}