很适合刚开始学C语言的同学。

1、C语言打印一条语句

源代码：

/* C Program to print a sentence. */

#include

int main()

{

printf("C Programming"); /* printf() prints the content inside quotation */

return 0;

}

输出：

C Programming

2、C语言打印用户输入的一个整数

源代码：

#include

int main()

{

int num;

printf("Enter a integer: ");

scanf("%d",&num);  /* Storing a integer entered by user in variable num */

printf("You entered: %d",num);

return 0;

}

输出：

Enter a integer: 25

You entered: 25

3、C语言实现两个整数相加

源代码：

/*C programming source code to add and display the sum of two integers entered by user */

#include

int main( )

{

int num1, num2, sum;

printf("Enter two integers: ");

scanf("%d %d",&num1,&num2); /* Stores the two integer entered by user in variable num1 and num2 */

sum=num1+num2;      /* Performs addition and stores it in variable sum */

printf("Sum: %d",sum);  /* Displays sum */

return 0;

}

输出：

Enter two integers: 12

11

Sum: 23

4、C语言实现两个小数相乘

源代码：

/*C program to multiply and display the product of two floating point numbers entered by user. */

#include

int main( )

{

float num1, num2, product;

printf("Enter two numbers: ");

scanf("%f %f",&num1,&num2);        /* Stores the two floating point numbers entered by user in variable num1 and num2 respectively */

product = num1*num2;  /* Performs multiplication and stores it */

printf("Product: %f",product);

return 0;

}

输出：

Enter two numbers: 2.4

1.1

Product: 2.640000

5、C语言查找字符的ASCII值

源代码：

/* Source code to find ASCII value of a character entered by user */

#include

int main(){

char c;

printf("Enter a character: ");

scanf("%c",&c);        /* Takes a character from user */

printf("ASCII value of %c = %d",c,c);

return 0;

}

输出：

Enter a character: G

ASCII value of G = 71

6、C语言根据用户输入的整数做商和余数

源代码：

/* C Program to compute remainder and quotient  */

#include

int main(){

int dividend, divisor, quotient, remainder;

printf("Enter dividend: ");

scanf("%d",&dividend);

printf("Enter divisor: ");

scanf("%d",&divisor);

quotient=dividend/divisor;           /*  Computes quotient */

remainder=dividend%divisor;          /* Computes remainder */

printf("Quotient = %d\n",quotient);

printf("Remainder = %d",remainder);

return 0;

}

输出：

Enter dividend: 25

Enter divisor: 4

Quotient = 6

Remainder = 1

7、C语言获取整型、单精度浮点型、双精度浮点型和字符型的长度

基本语法是：

temp = sizeof(operand);

/* Here, temp is a variable of type integer,i.e, sizeof() operator

returns integer value. */

源代码：

/* This program computes the size of variable using sizeof operator.*/

#include

int main(){

int a;

float b;

double c;

char d;

printf("Size of int: %d bytes\n",sizeof(a));

printf("Size of float: %d bytes\n",sizeof(b));

printf("Size of double: %d bytes\n",sizeof(c));

printf("Size of char: %d byte\n",sizeof(d));

return 0;

}

输出：

Size of int: 4 bytes

Size of float: 4 bytes

Size of double: 8 bytes

Size of char: 1 byte

注：可能会由于系统的不同出来的结果也不尽相同。

8、C语言获取关键字long的长度范围

源代码：

#include

int main(){

int a;

long int b;                /* int is optional. */

long long int c;            /* int is optional. */

printf("Size of int = %d bytes\n",sizeof(a));

printf("Size of long int = %ld bytes\n",sizeof(b));

printf("Size of long long int = %ld bytes",sizeof(c));

return 0;

}

输出：

Size of int = 4 bytes

Size of long int = 4 bytes

Size of long long int = 8 bytes

9、C语言交换数值

源代码：

#include

int main(){

float a, b, temp;

printf("Enter value of a: ");

scanf("%f",&a);

printf("Enter value of b: ");

scanf("%f",&b);

temp = a;    /* Value of a is stored in variable temp */

a = b;       /* Value of b is stored in variable a */

b = temp;    /* Value of temp(which contains initial value of a) is stored in variable b*/

printf("\nAfter swapping, value of a = %.2f\n", a);

printf("After swapping, value of b = %.2f", b);

return 0;

}

输出：

Enter value of a: 1.20

Enter value of b: 2.45

After swapping, value of a = 2.45

After swapping, value of b = 1.2

10、C语言检查数值是奇数还是偶数

源代码：

/*C program to check whether a number entered by user is even or odd. */

#include

int main(){

int num;

printf("Enter an integer you want to check: ");

scanf("%d",&num);

if((num%2)==0)      /* Checking whether remainder is 0 or not. */

printf("%d is even.",num);

else

printf("%d is odd.",num);

return 0;

}

输出1：

Enter an integer you want to check: 25

25 is odd.

输出2：

Enter an integer you want to check: 12

12 is even.

也可以用条件运算符解决：

/* C program to check whether an integer is odd or even using conditional operator */

#include

int main(){

int num;

printf("Enter an integer you want to check: ");

scanf("%d",&num);

((num%2)==0) ? printf("%d is even.",num) : printf("%d is odd.",num);

return 0;

}

11、C语言检查是元音还是辅音

源代码：

#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;

}

输出1：

Enter an alphabet: i

i is a vowel.

输出2：

Enter an alphabet: G

G is a consonant.

也可以用条件运算符解决

/* 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;

}

输出结果和上面的程序相同。

12、C语言实现从三个数值中查找最大值

实现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;

}

实现2：

/* C program to find largest number using if...else 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;

}

实现3：

/* C Program to find largest number using nested if...else 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;

}

输出结果相同：

Enter three numbers: 12.2

13.452

10.193

Largest number = 13.45

13、C语言解一元二次方程

源代码：

/* 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;

}

输出1：

Enter coefficients a, b and c: 2.3

4

5.6

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

输出2：

Enter coefficients a, b and c: 4

1

0

Roots are: 0.00 and -0.25