【自学编程】新手经常遇到的10大C语言基础算法，珍藏版源码值得收藏！

算法是一个程序和软件的灵魂，作为一名优秀的程序员，只有对一些基础的算法有着全面的掌握，才会在设计程序和编写代码的过程中显得得心应手。本文是近百个C语言算法系列的第二篇，包括了经典的Fibonacci数列、简易计算器、回文检查、质数检查等算法。也许他们能在你的毕业设计或者面试中派上用场。

1、计算Fibonacci数列

Fibonacci数列又称斐波那契数列，又称黄金分割数列，指的是这样一个数列：1、1、2、3、5、8、13、21。

C语言实现的代码如下：

/* Displaying Fibonacci sequence up to nth term where n is entered by user. */

#include <stdio.h>

int main()

{

int count, n, t1=0, t2=1, display=0;

printf("Enter number of terms: ");

scanf("%d",&n);

printf("Fibonacci Series: %d+%d+", t1, t2); /* Displaying first two terms */

count=2;    /* count=2 because first two terms are already displayed. */

while (count<n)

{

display=t1+t2;

t1=t2;

t2=display;

++count;

printf("%d+",display);

}

return 0;

}

结果输出：

Enter number of terms: 10

Fibonacci Series: 0+1+1+2+3+5+8+13+21+34+

也可以使用下面的源代码：

/* Displaying Fibonacci series up to certain number entered by user. */

#include <stdio.h>

int main()

{

int t1=0, t2=1, display=0, num;

printf("Enter an integer: ");

scanf("%d",&num);

printf("Fibonacci Series: %d+%d+", t1, t2); /* Displaying first two terms */

display=t1+t2;

while(display<num)

{

printf("%d+",display);

t1=t2;

t2=display;

display=t1+t2;

}

return 0;

}

结果输出：

Enter an integer: 200

Fibonacci Series: 0+1+1+2+3+5+8+13+21+34+55+89+144+

2、回文检查

源代码：

/* C program to check whether a number is palindrome or not */

#include <stdio.h>

int main()

{

int n, reverse=0, rem,temp;

printf("Enter an integer: ");

scanf("%d", &n);

temp=n;

while(temp!=0)

{

rem=temp%10;

reverse=reverse*10+rem;

temp/=10;

}

/* Checking if number entered by user and it's reverse number is equal. */

if(reverse==n)

printf("%d is a palindrome.",n);

else

printf("%d is not a palindrome.",n);

return 0;

}

结果输出：

Enter an integer: 12321

12321 is a palindrome.

3、质数检查

注：1既不是质数也不是合数。

源代码：

/* C program to check whether a number is prime or not. */

#include <stdio.h>

int main()

{

int n, i, flag=0;

printf("Enter a positive integer: ");

scanf("%d",&n);

for(i=2;i<=n/2;++i)

{

if(n%i==0)

{

flag=1;

break;

}

}

if (flag==0)

printf("%d is a prime number.",n);

else

printf("%d is not a prime number.",n);

return 0;

}

结果输出：

Enter a positive integer: 29

29 is a prime number.

4、打印金字塔和三角形

使用 * 建立三角形

 

源代码：

#include <stdio.h>

int main()

{

int i,j,rows;

printf("Enter the number of rows: ");

scanf("%d",&rows);

for(i=1;i<=rows;++i)

{

for(j=1;j<=i;++j)

{

printf("* ");

}

printf("\n");

}

return 0;

}

如下图所示使用数字打印半金字塔。

 

源代码：

#include <stdio.h>

int main()

{

int i,j,rows;

printf("Enter the number of rows: ");

scanf("%d",&rows);

for(i=1;i<=rows;++i)

{

for(j=1;j<=i;++j)

{

printf("%d ",j);

}

printf("\n");

}

return 0;

}

用 * 打印半金字塔

 

源代码：

#include <stdio.h>

int main()

{

int i,j,rows;

printf("Enter the number of rows: ");

scanf("%d",&rows);

for(i=rows;i>=1;--i)

{

for(j=1;j<=i;++j)

{

printf("* ");

}

printf("\n");

}

return 0;

}

用 * 打印金字塔

 

源代码：

#include <stdio.h>

int main()

{

int i,space,rows,k=0;

printf("Enter the number of rows: ");

scanf("%d",&rows);

for(i=1;i<=rows;++i)

{

for(space=1;space<=rows-i;++space)

{

printf("  ");

}

while(k!=2*i-1)

{

printf("* ");

++k;

}

k=0;

printf("\n");

}

return 0;

}

用 * 打印倒金字塔

 

源代码：

#include<stdio.h>

int main()

{

int rows,i,j,space;

printf("Enter number of rows: ");

scanf("%d",&rows);

for(i=rows;i>=1;--i)

{

for(space=0;space<rows-i;++space)

printf("  ");

for(j=i;j<=2*i-1;++j)

printf("* ");

for(j=0;j<i-1;++j)

printf("* ");

printf("\n");

}

return 0;

}

5、简单的加减乘除计算器

源代码：

/* Source code to create a simple calculator for addition, subtraction, multiplication and division using switch...case statement in C programming. */

# include <stdio.h>

int main()

{

char o;

float num1,num2;

printf("Enter operator either + or - or * or divide : ");

scanf("%c",&o);

printf("Enter two operands: ");

scanf("%f%f",&num1,&num2);

switch(o) {

case '+':

printf("%.1f + %.1f = %.1f",num1, num2, num1+num2);

break;

case '-':

printf("%.1f - %.1f = %.1f",num1, num2, num1-num2);

break;

case '*':

printf("%.1f * %.1f = %.1f",num1, num2, num1*num2);

break;

case '/':

printf("%.1f / %.1f = %.1f",num1, num2, num1/num2);

break;

default:

/* If operator is other than +, -, * or /, error message is shown */

printf("Error! operator is not correct");

break;

}

return 0;

}

结果输出：

Enter operator either + or - or * or divide : -

Enter two operands: 3.4

8.4

3.4 - 8.4 = -5.0

6、检查一个数能不能表示成两个质数之和

源代码：

#include <stdio.h>

int prime(int n);

int main()

{

int n, i, flag=0;

printf("Enter a positive integer: ");

scanf("%d",&n);

for(i=2; i<=n/2; ++i)

{

if (prime(i)!=0)

{

if ( prime(n-i)!=0)

{

printf("%d = %d + %d\n", n, i, n-i);

flag=1;

}

}

}

if (flag==0)

printf("%d can't be expressed as sum of two prime numbers.",n);

return 0;

}

int prime(int n)      /* Function to check prime number */

{

int i, flag=1;

for(i=2; i<=n/2; ++i)

if(n%i==0)

flag=0;

return flag;

}

结果输出：

Enter a positive integer: 34

34 = 3 + 31

34 = 5 + 29

34 = 11 + 23

34 = 17 + 17

7、用递归的方式颠倒字符串

源代码：

/* Example to reverse a sentence entered by user without using strings. */

#include <stdio.h>

void Reverse();

int main()

{

printf("Enter a sentence: ");

Reverse();

return 0;

}

void Reverse()

{

char c;

scanf("%c",&c);

if( c != '\n')

{

Reverse();

printf("%c",c);

}

}

结果输出：

Enter a sentence: margorp emosewa

awesome program

8、实现二进制与十进制之间的相互转换

/* C programming source code to convert either binary to decimal or decimal to binary according to data entered by user. */

#include <stdio.h>

#include <math.h>

int binary_decimal(int n);

int decimal_binary(int n);

int main()

{

int n;

char c;

printf("Instructions:\n");

printf("1. Enter alphabet 'd' to convert binary to decimal.\n");

printf("2. Enter alphabet 'b' to convert decimal to binary.\n");

scanf("%c",&c);

if (c =='d' || c == 'D')

{

printf("Enter a binary number: ");

scanf("%d", &n);

printf("%d in binary = %d in decimal", n, binary_decimal(n));

}

if (c =='b' || c == 'B')

{

printf("Enter a decimal number: ");

scanf("%d", &n);

printf("%d in decimal = %d in binary", n, decimal_binary(n));

}

return 0;

}

int decimal_binary(int n)  /* Function to convert decimal to binary.*/

{

int rem, i=1, binary=0;

while (n!=0)

{

rem=n%2;

n/=2;

binary+=rem*i;

i*=10;

}

return binary;

}

int binary_decimal(int n) /* Function to convert binary to decimal.*/

{

int decimal=0, i=0, rem;

while (n!=0)

{

rem = n%10;

n/=10;

decimal += rem*pow(2,i);

++i;

}

return decimal;

}

————————————

9、使用多维数组实现两个矩阵的相加

源代码：

#include <stdio.h>

int main(){

int r,c,a[100][100],b[100][100],sum[100][100],i,j;

printf("Enter number of rows (between 1 and 100): ");

scanf("%d",&r);

printf("Enter number of columns (between 1 and 100): ");

scanf("%d",&c);

printf("\nEnter elements of 1st matrix:\n");

/* Storing elements of first matrix entered by user. */

for(i=0;i<r;++i)

for(j=0;j<c;++j)

{

printf("Enter element a%d%d: ",i+1,j+1);

scanf("%d",&a[i][j]);

}

/* Storing elements of second matrix entered by user. */

printf("Enter elements of 2nd matrix:\n");

for(i=0;i<r;++i)

for(j=0;j<c;++j)

{

printf("Enter element a%d%d: ",i+1,j+1);

scanf("%d",&b[i][j]);

}

/*Adding Two matrices */

for(i=0;i<r;++i)

for(j=0;j<c;++j)

sum[i][j]=a[i][j]+b[i][j];

/* Displaying the resultant sum matrix. */

printf("\nSum of two matrix is: \n\n");

for(i=0;i<r;++i)

for(j=0;j<c;++j)

{

printf("%d  ",sum[i][j]);

if(j==c-1)

printf("\n\n");

}

return 0;

}

————————————

10、矩阵转置

源代码：

#include <stdio.h>

int main()

{

int a[10][10], trans[10][10], r, c, i, j;

printf("Enter rows and column of matrix: ");

scanf("%d %d", &r, &c);

/* Storing element of matrix entered by user in array a[][]. */

printf("\nEnter elements of matrix:\n");

for(i=0; i<r; ++i)

for(j=0; j<c; ++j)

{

printf("Enter elements a%d%d: ",i+1,j+1);

scanf("%d",&a[i][j]);

}

/* Displaying the matrix a[][] */

printf("\nEntered Matrix: \n");

for(i=0; i<r; ++i)

for(j=0; j<c; ++j)

{

printf("%d  ",a[i][j]);

if(j==c-1)

printf("\n\n");

}

/* Finding transpose of matrix a[][] and storing it in array trans[][]. */

for(i=0; i<r; ++i)

for(j=0; j<c; ++j)

{

trans[j][i]=a[i][j];

}

/* Displaying the transpose,i.e, Displaying array trans[][]. */

printf("\nTranspose of Matrix:\n");

for(i=0; i<c; ++i)

for(j=0; j<r; ++j)

{

printf("%d  ",trans[i][j]);

if(j==r-1)

printf("\n\n");

}

return 0;

}

结果输出：

 

看到这里你是不是对C语言又有了一点新的认知呢~

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