C語言基礎知識集錦

懂編程語言，有寫一些項目的`經驗，能夠看懂一些比較複雜項目的代碼對我們是十分有幫助的，下面小編為大家整理了一些C語言基礎知識，一起來看看吧：

　　1、C語言檢查是元音還是輔音

#include

int main(){

char c;

printf("Enter an alphabet: ");

scanf("%c",&c);

if(c=='a'||c=='A'||c=='e'||c=='E'||c=='i'||c=='I'||c=='o'||c=='O'||c=='u'||c=='U')

printf("%c is a vowel.",c);

else

printf("%c is a consonant.",c);

return 0;

}

輸出1：

Enter an alphabet: i

i is a vowel.

輸出2：

Enter an alphabet: G

G is a consonant.

也可以用條件運算符解決

/* C program to check whether a character is vowel or consonant using conditional operator */

#include

int main(){

char c;

printf("Enter an alphabet: ");

scanf("%c",&c);

(c=='a'||c=='A'||c=='e'||c=='E'||c=='i'||c=='I'||c=='o'||c=='O'||c=='u'||c=='U') ? printf("%c is a vowel.",c) : printf("%c is a consonant.",c);

return 0;

}

輸出結果和上面的程序相同。

　　2、C語言實現從三個數值中查找最大值

實現1：

/* C program to find largest number using if statement only */

#include

int main(){

float a, b, c;

printf("Enter three numbers: ");

scanf("%f %f %f", &a, &b, &c);

if(a>=b && a>=c)

printf("Largest number = %.2f", a);

if(b>=a && b>=c)

printf("Largest number = %.2f", b);

if(c>=a && c>=b)

printf("Largest number = %.2f", c);

return 0;

}

實現2：

/* C program to find largest number using statement */

#include

int main(){

float a, b, c;

printf("Enter three numbers: ");

scanf("%f %f %f", &a, &b, &c);

if (a>=b)

{

if(a>=c)

printf("Largest number = %.2f",a);

else

printf("Largest number = %.2f",c);

}

else

{

if(b>=c)

printf("Largest number = %.2f",b);

else

printf("Largest number = %.2f",c);

}

return 0;

}

實現3：

/* C Program to find largest number using nested statement */

#include

int main(){

float a, b, c;

printf("Enter three numbers: ");

scanf("%f %f %f", &a, &b, &c);

if(a>=b && a>=c)

printf("Largest number = %.2f", a);

else if(b>=a && b>=c)

printf("Largest number = %.2f", b);

else

printf("Largest number = %.2f", c);

return 0;

}

輸出結果相同：

Enter three numbers: 12.2

13.452

10.193

Largest number = 13.45

　　3、C語言解一元二次方程

/* Program to find roots of a quadratic equation when coefficients are entered by user. */

/* Library function sqrt() computes the square root. */

#include

#include /* This is needed to use sqrt() function.*/

int main()

{

float a, b, c, determinant, r1,r2, real, imag;

printf("Enter coefficients a, b and c: ");

scanf("%f%f%f",&a,&b,&c);

determinant=b*b-4*a*c;

if (determinant>0)

{

r1= (-b+sqrt(determinant))/(2*a);

r2= (-b-sqrt(determinant))/(2*a);

printf("Roots are: %.2f and %.2f",r1 , r2);

}

else if (determinant==0)

{

r1 = r2 = -b/(2*a);

printf("Roots are: %.2f and %.2f", r1, r2);

}

else

{

real= -b/(2*a);

imag = sqrt(-determinant)/(2*a);

printf("Roots are: %.2f+%.2fi and %.2f-%.2fi", real, imag, real, imag);

}

return 0;

輸出1：

Enter coefficients a, b and c: 2.3

4

5.6

Roots are: -0.87+1.30i and -0.87-1.30i

輸出2：

Enter coefficients a, b and c: 4

1

0

Roots are: 0.00 and -0.25

　　4、C語言檢查是否是閏年

/* C program to check whether a year is leap year or not using if else statement.*/

#include

int main(){

int year;

printf("Enter a year: ");

scanf("%d",&year);

if(year%4 == 0)

{

if( year%100 == 0) /* Checking for a century year */

{

if ( year%400 == 0)

printf("%d is a leap year.", year);

else

printf("%d is not a leap year.", year);

}

else

printf("%d is a leap year.", year );

}

else

printf("%d is not a leap year.", year);

return 0;

}

輸出1：

Enter year: 2000

2000 is a leap year.

輸出2：

Enter year: 1900

1900 is not a leap year.

輸出3：

Enter year: 2012

2012 is a leap year.