Thread: Need help with fibonacci sequence in c

On line #21, that semicolon says to the compiler that your while statement ends there, without any instructions. That results in an infinite loop if you input a number >= 0. Yes, C is weird like that sometimes. Remove it.

Here is an alternate version. For 32 bit signed integer, max input is 46.

Code:

#include <stdio.h>

int main() {
int num1 =  1;    /* fib(-1) */
int num2 = -1;    /* fib(-2) */
int num_r;
int num_t;
int temp;
    printf("Enter the number of times you want the Fibonacci sequence to be run: \n");
    scanf("%d", &num_t);
    for(num_r = 0; num_r <= num_t; num_r += 1){
        temp = num1;
        num1 = num1 + num2;
        num2 = temp;
        printf("%d\n", num1);
    }
    return 0;
}

or

Code:

#include <stdio.h>

int main() {
int num1 =  1;    /* fib(-1) */
int num2 = -1;    /* fib(-2) */
int num_r;
int num_t;
    printf("Enter the number of times you want the Fibonacci sequence to be run: \n");
    scanf("%d", &num_t);
    for(num_r = 0; num_r <= num_t; num_r += 1){
        num1 = num1 + num2;
        num2 = num1 - num2;
        printf("%d\n", num1);
    }
    return 0;
}