C语言实现密码设置及验证的方法和示例

#include <stdio.h>
#define PASSWORD_MAX_LEN 20

char* get_password() {
char password[PASSWORD_MAX_LEN + 1];
printf("Please enter your desired password: ");

fgets(password, sizeof(password), stdin);
// 去掉末尾换行符（fgets会读取包括'\n'在内的字符）
if (password[strlen(password) - 1] == '\n')
password[strlen(password) - 1] = '\0';

return strdup(password);
}

void set_and_verify_password() {
const char *storedPassword;
storedPassword = NULL;

while(storedPassword == NULL || strcmp(storedPassword, "your_initial_password") != 0){
free((void*)storedPassword);

// 获取新设定的密码
storedPassword = get_password();

printf("\nEnter the same password to verify:");

char *verifiedPasswd = get_password();

// 验证密码是否一致
int isMatched = strcmp(storedPassword, verifiedPasswd) ? 0 : 1;

free((void*)verifiedPasswd);

if (!isMatched)
puts("Passwords do not match! Please try again.");
}

printf("\nThe new password has been successfully set.\n");
}

int main(){
set_and_verify_password();
return 0;
}