C language is a very influential programming language, which is widely used in various computer systems and software development fields. This article will introduce you to 8 selected examples of C language programming to help you better master key skills and analyze classic codes.
- Output strings in reverse order
In C language, strings are character arrays, and you can output strings in reverse order by traversing the array. Here is sample code:
#include <stdio.h>
#include <string.h>
void reverse_string(char *str) {
int i, length = strlen(str);
for (i = length - 1; i >= 0; i--) {
printf("%c", str[i]);
}
}
int main() {
char str[] = "Hello, World!";
reverse_string(str);
return 0;
}
- Solve quadratic equations in one variable
Using C language to solve the quadratic equation in one variable, you can calculate the real root or imaginary root by judging the discriminant. Here is sample code:
#include <stdio.h>
#include <math.h>
void quadratic_solver(double a, double b, double c) {
double delta = b * b - 4 * a * c;
if (delta > 0) {
double x1 = (-b + sqrt(delta)) / (2 * a);
double x2 = (-b - sqrt(delta)) / (2 * a);
printf("Two real roots: x1 = %lf, x2 = %lf\n", x1, x2);
} else if (delta == 0) {
double x = -b / (2 * a);
printf("One real root: x = %lf\n", x);
} else {
printf("No real roots.\n");
}
}
int main() {
double a = 1, b = -3, c = 2;
quadratic_solver(a, b, c);
return 0;
}
- Find the maximum and minimum value in an array
In C language, you can traverse an array to find the maximum and minimum values. Here is sample code:
#include <stdio.h>
void find_max_min(int arr[], int size, int *max, int *min) {
*max = arr[0];
*min = arr[0];
for (int i = 1; i < size; i++) {
if (arr[i] > *max) {
*max = arr[i];
}
if (arr[i] < *min) {
*min = arr[i];
}
}
}
int main() {
int arr[] = {
2, 5, 8, 1, 0, -3, 12};
int max, min;
int size = sizeof(arr) / sizeof(arr[0]);
find_max_min(arr, size, &max, &min);
printf("Max: %d, Min: %d\n", max, min);
return 0;
}
- Calculate factorial
Factorial is a common mathematical operation, and a simple recursive function can be implemented in C language to calculate factorial. Here is sample code:
#include <stdio.h>
unsigned long long factorial(int n) {
if (n == 0) {
return 1;
} else {
return n * factorial(n - 1);
}
}
int main() {
int n = 10;
printf("%d! = %llu\n", n, factorial(n));
return 0;
}
- Fibonacci sequence
The Fibonacci sequence is a very famous sequence, and the calculation of the Fibonacci sequence can be realized in a recursive or circular manner. Here is sample code:
#include <stdio.h>
int fibonacci(int n) {
if (n <= 1) {
return n;
} else {
return fibonacci(n - 1) + fibonacci(n - 2);
}
}
int main() {
int n = 10;
printf("The %dth Fibonacci number is: %d\n", n, fibonacci(n));
return 0;
}
- string concatenation
In C language, you can use the string pointer and array traversal to realize the string splicing function. Here is sample code:
#include <stdio.h>
#include <string.h>
void string_concat(char *dest, const char *src) {
int dest_len = strlen(dest);
int src_len = strlen(src);
for (int i = 0; i <= src_len; i++) {
dest[dest_len + i] = src[i];
}
}
int main() {
char dest[50] = "Hello, ";
const char *src = "World!";
string_concat(dest, src);
printf("Concatenated string: %s\n", dest);
return 0;
}
- binary search
Binary search is an efficient search algorithm that works on sorted arrays. Here is sample code:
#include <stdio.h>
int binary_search(int arr[], int size, int target) {
int left = 0, right = size - 1;
while (left <= right) {
int mid = left + (right - left) / 2;
if (arr[mid] == target) {
return mid;
} else if (arr[mid] < target) {
left = mid + 1;
} else {
right = mid - 1;
}
}
return -1;
}
int main() {
int arr[] = {
1, 3, 5, 7, 9, 11, 13};
int target = 7;
int size = sizeof(arr) / sizeof(arr[0]);
int index = binary_search(arr, size, target);
printf("Index of %d is: %d\n", target, index);
return 0;
}
- dynamic memory allocation
In C language, you can use dynamic memory allocation functions (such as malloc and free) to implement dynamic arrays. Here is sample code:
#include <stdio.h>
#include <stdlib.h>
int main() {
int n = 5;
int *arr = (int *)malloc(n * sizeof(int));
if (arr == NULL) {
printf("Memory allocation failed.\n");
return 1;
}
for (int i = 0; i < n; i++) {
arr[i] = i * 2;
}
printf("Dynamic array: ");
for (int i = 0; i < n; i++) {
printf("%d ", arr[i]);
}
printf("\n");
free(arr);
return 0;
}
The above are 8 selected examples of C language programming, hoping to help you improve your programming skills. In fact, there are many other practical techniques and methods in C language. Through continuous learning and practice, you will be able to master C language programming more deeply.