1

54321

void count_down (int count) {

for(i=count; i>1; i--)printf(" %d\t", count);

}

printf("A%d\n", count);if(count>1) count_down(count-1);printf("B%d\n", count);

main (){count_down(5);

}

A5A4A3A2A1

Recursion 遞歸

Recursion

A5

count_down(4);

B5

A4

count_down(3);

B4

A3

count_down(2);

B3

A2count_down(1);B2

B1B2B3B4B5

A1B1

2

countDown(4)

countDown(3)printf("A%i", count);

printf("B%i", count);

countDown(2)printf("A%i", count);

printf("B%i", count);

countDown(1)printf("A%i", count);

printf("B%i", count);

A4

A3

A2

printf("A%i", count);

printf("B%i", count);countDown(?)

A1

B1

B2

B3

B4

Recursion

A4A3A2A1

B1B2B3B4

3

void count_down (int count) {

}

printf("A%d\n", count);if(count>1) count_down(count-1);printf("B%d\n", count);

main (){count_down(4);

}

Recursion 遞歸

Recursion

A4

B4

4321

A3

B3

A2

B2

A1

B1