C语言零基础入门习题（九）斐波那契数列

C语言零基础入门习题（九）斐波那契数列

前言 

        C语言是大多数小白走上程序员道路的第一步，在了解基础语法后，你就可以来尝试解决以下的题目。放心，本系列的文章都对新手非常友好。

Tips：题目是英文的，但我相信你肯定能看懂

一、The Fibonacci sequence is 0, 1, 1, 2, 3, 5, 8, 13... where the first two terms are 0 and 1, and each term thereafter is defined recursively as the sum of the two preceding terms; that is

Fib(n)=n for n< 2

Fib{n) = Fib(n-1) + Fib(n-2) for n >= 2

a. Write a recursive function that returns the nth number in a Fibonacci sequence when n is passed to the function as an argument.

For example, when n = 8, the function returns the 8th number in the sequence, which is 13.

#include <stdio.h>
int fib(int);int main()
{int n;scanf("%d",&n);printf("%d",fib(n));return 0;
}
int fib(int n)
{int s;if(n<3)   return n-1;return fib(n-1)+fib(n-2);
}

b. Write a function that uses repetition without array to calculate the nth term of a Fibonacci sequence.

#include <stdio.h>int main()
{int n,a=1,b=0,c=1,i;scanf("%d",&n);if(n<3)   a=n-1;else{for(i=3;i<=n;i++){a=b+c;b=c;c=a;}}printf("%d",a);return 0;
}

c. Write a function that uses repetition and array to calculate the nth term of a Fibonacci sequence.

#include <stdio.h>int main()
{int a[9999];int n,i;scanf("%d",&n);for(i=1;i<=n;i++){if(i<3)   a[i]=i-1;else    a[i]=a[i-1]+a[i-2];}printf("%d",a[n]);return 0;
}

二、Write a program that will read five values from the keyboard and store them in an array of type float with the name amounts.

Create two arrays of five elements of type long with the names dollars and cents. Store the whole number part of each value in the amounts array in the corresponding element of dollars and the fractional part of the amount as a two-digit integer in cents (e.g., 2.75 in amounts[1] would result in 2 being stored in dollars[1] and 75 being stored in cents[1]). Output the values from the two arrays of type long as monetary amounts.

#include <stdio.h>int main()
{float amounts[4];long dollars[4], cents[4];int i;for(i=0;i<5;i++){scanf("%f",&amounts[i]);dollars[i]=(int)amounts[i];cents[i]=(amounts[i]-dollars[i])*100;printf("dollar=%ld, cent=%ldn",dollars[i], cents[i]);}return 0;
}

三、Write a C program that includes two functions named calcAvg() and variance ().

The calcAvg() func-tion should calculate and return the average of the values stored in an array named testvals. The array should be declared in main () and include the values 89, 95, 72, 83, 99, 54, 86, 75, 92, 73, 79, 75, 82, 73. The variance () function should calculate and return the variance of the data. The variance is obtained by subtracting the average from each value in testvals, squaring the differences obtained, adding their squares, and dividing by the number of elements in testvals. The values returned from calcAvg() and variance () should be displayed using printf () function calls in main ()。

#include <stdio.h>
void calcAvg(int[], float*);
void variance (int[], float*);int main()
{float a,b;int testvals[14]={89, 95, 72, 83, 99, 54, 86, 75, 92, 73, 79, 75, 82, 73};calcAvg(testvals, &a);variance (testvals, &b);printf("average = %gn",a);printf("variance = %g",b);return 0;
}
void calcAvg(int t[], float* ps)
{int i;float s=0;for(i=0;i<14;i++)s+=t[i];*ps=s/14;
}
void variance (int t[], float* pv)
{int i;float v=0;for(i=0;i<14;i++)v=v+(t[i]-80.5)*(t[i]-80.5);*pv=v/14;
}

四、Write a program that prompts the user to enter three sets of five double numbers each.

(You may assume the user responds correctly and doesn’t enter non-numeric data.) The program should accomplish all of the following:

1. Store the information in a 3×5 array.
2. Compute the average of each set of five values.
3. Compute the average of all the values.
4. Determine the largest value of the 15 values.
5. Report the results.

Each major task should be handled by a separate function using the traditional C approach to handling arrays. Accomplish task“b”by using a function that computes and returns the average of a one-dimensional array; use a loop to call this function three times. The other tasks should take the entire array as an argument, and the functions performing tasks“c”and “d”should return the answer to the calling program.

#include <stdio.h>
void ave(double [3][5], double*, double*);
void max(double [3][5], double*);int main()
{double a[3][5],b[3];double a1,m;int i,j;printf("pls enter three sets of five double numbers each:");for(i=0;i<3;i++)for(j=0;j<5;j++)scanf("%lf",&a[i][j]);ave(a,&a1,&b);printf(" the average of each set of five values:%g %g %gn",b[0],b[1],b[2]);printf(" the average of all the values:%gn",a1);max(a,&m);printf("the largest value of the 15 values:%gn",m);return 0;
}
void ave(double a[3][5], double*a1,double*b)
{int i,j;double s=0;for(i=0;i<3;i++)for(j=0;j<5;j++){s+=a[i][j];b[i]+=a[i][j];}for(i=0;i<3;i++)b[i]=b[i]/5;*a1=s/15;
}
void max(double a[3][5], double*m)
{int i,j;*m=a[0][0];for(i=0;i<3;i++){for(j=0;j<5;j++)if(a[i][j]>*m)   *m=a[i][j];}
}

总结

以上就是本文全部内容，你学会了吗？