初学编程100个代码c

很高兴听到你想要学习编程！下面是一些适合初学者的简单代码示例：

1. 输出“Hello, world!”

#include <stdio.h>

int main() {
    printf("Hello, world!\n");
    return 0;
}

2. 计算两个数之和

#include <stdio.h>

int main() {
    int a, b, sum;
    printf("Enter two numbers: ");
    scanf("%d %d", &a, &b);
    sum = a + b;
    printf("The sum is %d\n", sum);
    return 0;
}

3. 判断一个数是否是偶数

#include <stdio.h>

int main() {
    int num;
    printf("Enter a number: ");
    scanf("%d", &num);
    if (num % 2 == 0) {
        printf("%d is even.\n", num);
    } else {
        printf("%d is odd.\n", num);
    }
    return 0;
}

4. 打印九九乘法表

#include <stdio.h>

int main() {
    int i, j;
    for (i = 1; i <= 9; i++) {
        for (j = 1; j <= i; j++) {
            printf("%d*%d=%d\t", j, i, i*j);
        }
        printf("\n");
    }
    return 0;
}

5. 求一个数的阶乘

#include <stdio.h>

int main() {
    int num, i, fact = 1;
    printf("Enter a number: ");
    scanf("%d", &num);
    for (i = 1; i <= num; i++) {
        fact *= i;
    }
    printf("%d! = %d\n", num, fact);
    return 0;
}

6. 判断一个数是否是质数

#include <stdio.h>

int main() {
    int num, i, flag = 0;
    printf("Enter a number: ");
    scanf("%d", &num);
    for (i = 2; i <= num/2; i++) {
        if (num % i == 0) {
            flag = 1;
            break;
        }
    }
    if (num == 1) {
        printf("1 is neither prime nor composite.\n");
    } else {
        if (flag == 0) {
            printf("%d is prime.\n", num);
        } else {
            printf("%d is not prime.\n", num);
        }
    }
    return 0;
}

7. 计算斐波那契数列

#include <stdio.h>

int main() {
    int n, i, t1 = 0, t2 = 1, nextTerm;
    printf("Enter the number of terms: ");
    scanf("%d", &n);
    printf("Fibonacci Series: ");
    for (i = 1; i <= n; i++) {
        printf("%d, ", t1);
        nextTerm = t1 + t2;
        t1 = t2;
        t2 = nextTerm;
    }
    return 0;
}

8. 排序一个整数数组

#include <stdio.h>

int main() {
    int arr[100], n, i, j, temp;
    printf("Enter the number of elements in the array: ");
    scanf("%d", &n);
    printf("Enter the elements:\n");
    for (i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }
    for (i = 0; i < n-1; i++) {
        for (j = 0; j < n-i-1; j++) {
            if (arr[j] > arr[j+1]) {
                temp = arr[j];
                arr[j] = arr[j+1];
                arr[j+1] = temp;
            }
        }
    }
    printf("Sorted array:\n");
    for (i = 0; i < n; i++) {
        printf("%d ", arr[i]);
    }
    return 0;
}

9. 计算圆的面积和周长

#include <stdio.h>

#define PI 3.14159

int main() {
    float radius, area, perimeter;
    printf("Enter the radius of the circle: ");
    scanf("%f", &radius);
    area = PI * radius * radius;
    perimeter = 2 * PI * radius;
    printf("Area = %f\nPerimeter = %f\n", area, perimeter);
    return 0;
}

10. 将一个十进制数转换为二进制数

#include <stdio.h>

int main() {
    int dec, rem, i = 0;
    int bin[100];
    printf("Enter a decimal number: ");
    scanf("%d", &dec);
    while (dec != 0) {
        rem = dec % 2;
        bin[i] = rem;
        dec /= 2;
        i++;
    }
    printf("Binary number: ");
    for (i = i-1; i >= 0; i--) {
        printf("%d", bin[i]);
    }
    printf("\n");
    return 0;
}