函数被调用但没有做任何事情

Question

我正在使用链表在 c 上创建一个学生管理系统。我创建了一个名为搜索的功能，它从四个选项之一获取用户的输入，然后对学生列表执行搜索操作。

struct Program { //structure to hold information of program
    char p_name[50];    //name of program
    char p_code[10];    //code of program
    char responsible[50];   //person responsible for program
    char r_email[50];   //email of responsible
    struct Program* next;
};

struct Student {    //structure to hold information of student
    int personal_no;
    char name[50];
    char gender[6];
    struct Program *study_program;
    int age;
    char email[50];
    struct Student* next;
};

代码没有优化，我会努力做得更好，但这里是功能：

void studyProgram(struct Student *head) {
    struct Student * t = NULL;
    struct Program* temp = programs;
    while (temp != NULL) {
        int count = 0;
        int male = 0; int female = 0;
        float age = 0;
        printf("Program: %s\n", temp->p_name);
        t = head;
        while (t != NULL) {
            if (!strcmp(temp->p_code, t->study_program->p_code)) {
                count++;
                age += t->age;
                if (!strcmp(_strupr(t->gender), "MALE")) {
                    male++;
                }
                else {
                    female++;
                }
            }
            t = t->next;
        }
        age = age / count;
        printf("Number of Students: %d\n", count);
        printf("Number of Males: %d\n", male);
        printf("Number of Females: %d\n", female);
        printf("Average age: %f\n", age);
        temp = temp->next;
    }
}

void search(struct Student *head)
{
    int p;
    struct Student * temp = head;
    int ch;
    printf("What do you want to search for:\n");
    printf("1.Personal Number\n2.Name\n3.Study Program\n4.Statistics\nOption: ");
    scanf("%d", &ch);
    if (ch == 1) {
        printf("Enter personal number:\n");
        scanf("%n", &p);
        while(temp!=NULL) {
            if(temp->personal_no == p){
                display(temp);
            return;
            }
            temp = temp->next;
        }
    }
    else if (ch == 2) {
        char n[50];
        printf("Enter name:\n");
        scanf("%s", n);
        while(temp!=NULL) {
            if(!strcmp(temp->name, n)){
                display(temp);
            return;
            }
            temp = temp->next;
        }
    }
    else if (ch == 3) {
        char n[10];
        printf("Enter program code:\n");
        scanf("%s", n);
        while(temp!=NULL) {
            if(!strcmp(temp->study_program->p_code, n)) {
                display(temp);
            }
            temp = temp->next;
        }
    }
    else if (ch == 4) {
        int count = 0;
        int male = 0; int female = 0;
        float age = 0;
        
        while(temp!=NULL) {
            count++;
            age += temp->age;
            if(!strcmp(strupr(temp->gender), "MALE")){
                male++;
            }
            else {
                female++;
            }
            temp = temp->next;
        }
        age = age / count;
        printf("Number of Students: %d\n", count);
        printf("Number of Males: %d\n", male);
        printf("Number of Females: %d\n", female);
        printf("Average age: %f\n", age);
        studyProgram(head);
    }
}

void display(struct Student *head)
{
    struct Student * temp = head;
    while(temp!=NULL){
        printf("Peronsal No: %d\n", temp->personal_no);
        printf("Name: %s\n", temp->name);
        printf("Gender %s\n", temp->gender);
        printf("Study Program: %n\n", temp->study_program->p_name);
        printf("Age: %d\n", temp->age);
        printf("Email: %s\n", temp->email);
        temp = temp->next;
    }
}

选项 1-3 执行不言自明的基本搜索操作。选项 4 提供的信息首先是球员总数、男性和女性人数，然后是他们的平均年龄。然后调用学习计划函数，为每个学习计划计算相同的属性。

programs是一个全局变量结构，包含程序（CS，AI）的所有信息。

卡在这个问题上好久了，想不出解决办法。 studyProgram 函数根本不起作用。显示功能不显示任何信息。在情况 1 中，对于个人号码，选择选项时将跳过输入。

谁能指出我哪里出错了？

programs是一个全局变量，包含程序（CS，AI）的所有信息。