c++学生成绩管理系统

#include 
#include 
#include 

#define MAX_STUDENTS 100 
#define MAX_NAME_LEN 20
#define MAX_ID_LEN 13
#define MAX_STUDENTS 100

typedef struct {
    char first_name[MAX_NAME_LEN];
    char last_name[MAX_NAME_LEN];
    char id[MAX_ID_LEN];
    float score;
    float gpa;
    char rebuild;
	const char* gpa_grade;

} Student;

void add_student(Student students[], int n);
void modify_student(Student students[], int n);
void calculate_gpa(Student students[], int n);
void show_all_info(Student students[],int n);
void sort_by_score(Student students[],int n);
void search(Student students[],int n);
void encrypt(Student students[],int n);
void encryptString(char *str, int key);
void decrypt(char *str, int key);
char encryptedString[MAX_STUDENTS * 3 + 1]; // 每个成绩最多占3个字符，再加上结尾的空字符('\0')

int main() {
    Student students[MAX_STUDENTS];
    int i, choice, n ,N;
//	encryptedString[0] = '\0'; // 初始化为空字符串
//    得到用户想先输入的学生数 
	printf("请输入初始数据个数：\n"); 
	scanf("%d",&N);  
	n=N;
//	输入初始数据
	printf("请输入初始数据:\n"); 
 	for(int i=0;i= MAX_STUDENTS) {
                    printf("Cannot add more students. Maximum limit reached.\n");
                    break;
                }
                add_student(students, n);
                n++;
                break;

            case 2:
                if (n == 0) {
                    printf("No students added yet.\n");
                    break;
                }
                modify_student(students, n);
                break;

            case 3:
                if (n == 0) {
                    printf("No students added yet.\n");
                    break;
                }
                calculate_gpa(students, n);
                break;
			
			case 4:
				show_all_info(students,n);
				break;
				
			case 5:
				sort_by_score(students,n);
				show_all_info(students,n);
				break;
			case 6:
				search(students,n);
				break;
			case 7:
				encrypt(students,n);
				break;
			
			case 8:
				int key;
				printf("请输入密钥");
				scanf("%d",&key); 
				decrypt(encryptedString, key);
				break;
            case 9:
                exit(0);

            default:
                printf("Invalid choice. Please try again.\n");
        }
    }

    return 0;
}

void add_student(Student students[], int n) {
    printf("\nEnter details of student %d:\n", n + 1);
    printf("First name: ");
    scanf("%s", students[n].first_name);
    printf("Last name: ");
    scanf("%s", students[n].last_name);
    printf("ID: ");
    scanf("%s", students[n].id);
    printf("Score: ");
    scanf("%f", &students[n].score);
}

void modify_student(Student students[], int n) {
    char id[MAX_ID_LEN];
    int i;

    printf("\nEnter ID of student to modify: ");
    scanf("%s", id);

    for (i = 0; i < n; i++) {
        if (strcmp(students[i].id, id) == 0) {
            printf("Enter new details for student %d:\n", i + 1);
            printf("First name: ");
            scanf("%s", students[i].first_name);
            printf("Last name: ");
            scanf("%s", students[i].last_name);
            printf("ID: ");
            scanf("%s", students[i].id);
            printf("Score: ");
            scanf("%f", &students[i].score);
            return;
        }
    }

    printf("Student with ID %s not found.\n", id);
}

void calculate_gpa(Student students[], int n) {
    int i;
    float total_score = 0, total_gpa = 0;

    for (i = 0; i < n; i++) {
        if (students[i].score >= 92) {
            students[i].gpa = 4.5;
        } else if (students[i].score >= 88) {
            students[i].gpa = 4.0;
        } else if (students[i].score >=80 ) {
            students[i].gpa = 3.5;
        } else if (students[i].score >= 75) {
            students[i].gpa = 3.0;
        } else if (students[i].score >= 70) {
            students[i].gpa = 2.5;
        } else if (students[i].score >= 60) {
            students[i].gpa = 2.0;
        } else {
            students[i].gpa = 0.0;
        }

        total_score += students[i].score;
        total_gpa += students[i].gpa;
    }

    printf("\nGPA of each student:\n");
    for (i = 0; i < n; i++) {
        printf("%s %s: %.2f\n", students[i].first_name, students[i].last_name, students[i].gpa);
    }

    printf("Average score: %.2f\n", total_score / n);
    printf("Average GPA: %.2f\n", total_gpa / n);
}

void show_all_info(Student students[], int n){
	printf("-----------------------------------\n");
	printf("姓名    绩点 等级 分数 是否重修\n"); 
    for (int i = 0; i < n; i++) {
        if (students[i].score >= 92) {
            students[i].gpa = 4.5;
        } else if (students[i].score >= 88) {
            students[i].gpa = 4.0;
        } else if (students[i].score >= 80) {
            students[i].gpa = 3.5;
        } else if (students[i].score >= 75) {
            students[i].gpa = 3.0;
        } else if (students[i].score >= 70) {
            students[i].gpa = 2.5;
        } else if (students[i].score >= 60) {
            students[i].gpa = 2.0;
        } else {
            students[i].gpa = 0.0;
        }
        
//	评判A+等级 
	    if (students[i].gpa >= 4.5) {
	        students[i].gpa_grade = "A+";
	    } else if (students[i].gpa >= 4.0) {
	        students[i].gpa_grade = "A";
	    } else if (students[i].gpa >= 3.5) {
	        students[i].gpa_grade = "B+";
	    } else if (students[i].gpa >= 3.0) {
	        students[i].gpa_grade = "B";
	    } else if (students[i].gpa >= 2.5) {
	        students[i].gpa_grade = "C+";
	    } else if (students[i].gpa >= 2.0) {
	        students[i].gpa_grade = "C";
	    } else if (students[i].gpa >= 1.5) {
	        students[i].gpa_grade = "D";
	    } else {
	        students[i].gpa_grade = "F";
	    }
        if (strncmp(students[i].id, "2022", 4) == 0){
        	students[i].rebuild= 0; 
		}
		else{
			students[i].rebuild= 1;
		}

		printf("%s %s  %.1f  %s  %.1f  %s",students[i].first_name, students[i].last_name, students[i].gpa, students[i].gpa_grade, students[i].score,students[i].rebuild?"是":"否");
	
		printf("\n");
	}
	printf("-----------------------------------");
}

void sort_by_score(Student students[],int n){
	for (int i = 0; i < n - 1; i++) {
        for (int j = 0; j = 92) {
	            students[i].gpa = 4.5;
	        } else if (students[i].score >= 88) {
	            students[i].gpa = 4.0;
	        } else if (students[i].score >= 80) {
	            students[i].gpa = 3.5;
	        } else if (students[i].score >= 75) {
	            students[i].gpa = 3.0;
	        } else if (students[i].score >= 70) {
	            students[i].gpa = 2.5;
	        } else if (students[i].score >= 60) {
	            students[i].gpa = 2.0;
	        } else {
	            students[i].gpa = 0.0;
	        }
		
				printf("%s %s %.1f %.1f",students[i].first_name, students[i].last_name, students[i].gpa, students[i].score);
				printf("\n");
				
				printf("-----------------------------------");
			}
		}
		if(flag !=1){
			printf("The student's infomation not exit");
		}
	}

}

void encryptString(char *str, int key) {
    int length = strlen(str);
    for (int i = 0; i < length; i++) {
        int digit = str[i] - '0'; // 将字符转换为数字
        int encryptedDigit = (digit + key) % 10; // 加密运算
        str[i] = encryptedDigit + '0'; // 将加密后的数字转换回字符
    }
}

void encrypt(Student students[],int n){
	int key;
//	char encryptedString[MAX_STUDENTS * 3 + 1]; // 每个成绩最多占3个字符，再加上结尾的空字符('\0')
//	encryptedString[0] = '\0'; // 初始化为空字符串
	printf("请输入密钥："); 
	scanf("%d",&key);
	    // 将成绩拼接为字符串
    for (int i = 0; i < n; i++) {
        char scoreString[4]; // 3个字符用于存储成绩，再加上结尾的空字符('\0')
        snprintf(scoreString, sizeof(scoreString), "%.0f",students[i].score);
        strcat(encryptedString, scoreString);
    }
    printf("加密前的字符串：%s\n", encryptedString);
        // 加密字符串
    encryptString(encryptedString, key);

    printf("加密后的字符串：%s\n", encryptedString);

}


void decrypt(char *str, int key) {
    int length = strlen(str);
    for (int i = 0; i < length; i++) {
        int digit = str[i] - '0'; // 将字符转换为数字
        int decryptedDigit = (digit - key+10) % 10; // 解密运算
        str[i] = decryptedDigit + '0'; // 将解密后的数字转换回字符
    }
    printf("解密后的字符串：%s\n", str);
}