栈的作用之递归,波兰表达式——C语言描述
栈的作用之递归,波兰表达式——C语言描述
1 斐波拉契数列
公式:f(0) = 0, f(1) = 1, f(n) = f(n - 1) + f(n - 2);(n>2)
(1)循环实现
代码:
void FabByArr(void) {
int i;
int RecArr[5];
RecArr[0] = 0;
RecArr[1] = 1;
for (i = 2; i < 5; ++i) {
RecArr[i] = RecArr[i - 2] + RecArr[i - 1];
}
for (i = 0; i < 5; ++i) {
printf("RecArr[%d] = %d\n", i, RecArr[i]);
}
}
结果:
RecArr[0] = 0
RecArr[1] = 1
RecArr[2] = 1
RecArr[3] = 2
RecArr[4] = 3
(2)递归
每调用一层函数时,就入栈,那层函数实现后就出栈
代码:
int FabRec(int i) {
if (0 == i) {
return 0;
}
else if (1 == i) {
return 1;
}
return FabRec(i - 2) + FabRec(i - 1);
}
void PrintFabByRec(void) {
int i = 0;
for (i = 0; i < 5; ++i) {
printf("The %d value = %d\n", i, FabRec(i));
}
}
结果:
The 0 value = 0
The 1 value = 1
The 2 value = 1
The 3 value = 2
The 4 value = 3