Example 5-8 Fibonacci sequence
Title description
Enter a positive integer n to find the nth number in the Fibonacci sequence. The characteristics of Fibonacci sequence: the first and second numbers are 1,1. Starting from the third number, the summary is the sum of the previous two numbers. That is: the
input of the positive integer n is not more than 50.
Enter
a positive integer not more than 50 to
output
the nth number of the Fibonacci sequence, and output a newline at the end.
Sample input Copy
20
Sample output Copy
6765
#include <stdio.h>
int main(void) {
int a;
int b[50] = {
1, 1};
scanf("%d", &a);
if (a == 1 || a == 2) {
printf("%d", b[0]);
} else if (a > 2) {
for (int i = 2; i < a; ++i) {
b[i] = b[i - 1] + b[i - 2];
}
}
printf("%d", b[a - 1]);
return 0;
}