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);
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335