函式递回

13 函式递回的理解：

13.1 （使用函式）数数字的练习

#include <stdio.h>
void countTo1 (int);


int main()
{
    countTo1(1);
    return 0;
    
}

void countTo1(int i) {
    if (i <= 3) {
        countTo1(i+1);
        printf("%d\n", i); // 这里的另一种写法是 printf("%d\n", i); countTo1(i+1);
    }
}

 13.2 （使用函式）求连续整数和的练习（有递回）

#include <stdio.h>
int sum(int N);

int main() {
    int N;
    printf("N = ");
    scanf("%d", &N);
    printf("%d\n", sum(N));
    return 0;
}

int sum (int N) {
    if (N == 1) {
        return 1;
    }
    return sum(N-1) + N;
}

N = 1000
500500

Process returned 0 (0x0)   execution time : 20.777 s
Press any key to continue.

13.3 求上楼梯的方法数的练习

#include <stdio.h>
int S(int);


int main() {
    int N;
    printf("N = ");
    scanf("%d", &N);
    printf("%d\n", S(N));
    return 0;
}

int S(int N) {
    if (N <= 2) {
        return N;
    }
    return S(N-1) + S(N-2);
}


N = 10
89

Process returned 0 (0x0)   execution time : 4.986 s
Press any key to continue.