c用for循环打印三角形,直角,空心直角,等腰,等腰空心

直角三角形 t11.c
#include

main() {
        int i,j;
        for (i=1;i<=10;i++) {
                for (j=1;j<=i;j++) {
                        printf("*");
                }
                printf("\n");
        }
}

直角空心三角形 t12.c
#include

main() {
        int i,j;
        for (i=1;i<=10;i++) {
                for (j=1;j<=i;j++) {
                        if (j==1 || j==i || i==10)
                                printf("*");
                        else
                                printf(" ");

                }
                printf("\n");
        }
}

等腰三角形 t13.c
#include

main() {
        int i,j;
        for (i=1;i<=10;i++) {
                for (j=1;j<=10-i;j++)
                        printf(" ");

                for (j=1;j<=2*i-1;j++)
                        printf("*");

                printf("\n");
        }
}

等腰空心三角形 t14.c
#include

main() {
        int i,j;
        for (i=1;i<=10;i++) {
                for (j=1;j<=10-i;j++)
                        printf(" ");

                for (j=1;j<=2*i-1;j++) {
                        if (j==1 || j==2*i-1 || i==10)
                                printf("*");
                        else
                                printf(" ");
                }
                printf("\n");
        }
}