如何在 C 中创建一个函数来搜索文件中包含所选字符的行？

Question

Sorry if the title is confusing. It might be better if I explain with the below code blocks.

Part of my code

typedef struct {
    char name[50];
    char num[9];
    char email[50];
} Contacts;
Contacts Contact[50];

void search() {
    char string[20];
    printf("What are you searching for: ");
    scanf("%19s", string);
    file = fopen("StoredContacts.txt", "r");
    while (!feof(file)) {
        
    }
}

StoredContacts.txt

Bobby,10,bobby@gmail.com
Abby,30,abby@gmail.com
Ada,20,ada@gmail.com

So basically my StoredContacts.txt contains names, ages and emails. I separated the contacts with a comma and they can be correctly registered into Contact.

What I want my search() to do is when I entered what I was looking for, the function would check each Contact and return me the full details of the person(s) I was looking for. For example, if I entered "A", I want it to print "Abby,30,abby@gmail.com" and "Ada,20,ada@gmail.com". If I entered "da", I want it to return "Ada,20,ada@gmail.com". I tried using bsearch and realised it couldn't print the details of the person(s).

Answer 1

I used strstr and finally made the search function.

The function now at first tests if there are any results that contain the string, then it runs again and prints the details of the person that contains the string in their name or age, or email.

void search() {
int result_count = 0;
char string[20];
char *result1, *result2, *result3;
printf("What are you searching for: ");
scanf("%19s", string);
file = fopen("StoredContacts.txt", "r");
if (!feof(file)) {
    for (int i = 0; i < stored; i++) {
        result1 = strstr(Contact[i].name,string);
        result2 = strstr(Contact[i].num,string);
        result3 = strstr(Contact[i].email,string);
        if (result1 || result2 || result3) {
            result_count++;
        }
    }
}
if (result_count > 0) {
    printf("There are %d results:\n", result_count);
    if (!feof(file)) {
        for (int i = 0; i < stored; i++) {
            result1 = strstr(Contact[i].name,string);
            result2 = strstr(Contact[i].num,string);
            result3 = strstr(Contact[i].email,string);
            if (result1 || result2 || result3) {
                printf("%s,%s,%s\n", Contact[i].name, Contact[i].num, Contact[i].email);
            }
        }
    }
}
else if (result_count <= 0) {
    printf("None of the contacts contains %s", string);
} 
fclose(file);
menu();