执行showStudents()函数时C语言程序崩溃问题求助

Hey there! Let's break down why your showStudents() function is crashing and fix those issues step by step:

Key Issues Causing the Crash & Incorrect Output #

1. Off-by-one Error in Loop: Your loop runs i <= count, but count is the number of students added. Since array indices start at 0, valid indices are 0 to count-1. Accessing v[count] (when i == count) reads uninitialized memory, leading to crashes or garbage data.
2. Wrong Format Specifier for Age: You're using %s (for strings) to print v[i].age, which is an integer. This mismatch causes undefined behavior—definitely a crash trigger!
3. Missing Header for bool: The code uses bool but doesn't include <stdbool.h>, which will cause compilation errors in standard C.
4. Non-Standard main() Declaration: main() should return an int per C standards.

Fixed Code #

#include <stdio.h>
#include <stdbool.h>  // Added for bool type

int count = 0; // Global count of students

struct student{
    char name[20];
    char surname[20];
    int age;
    char registrationDate[10];
} v[200];

void addStudents(){
    printf("\nJu po shtoni nje student te ri ne liste!\n");
    printf("\nShkruani emrin: ");
    scanf("%s", v[count].name); // Removed unnecessary & (array decays to pointer)
    printf("\nShkruani mbiemrin: ");
    scanf("%s", v[count].surname);
    printf("\nShkruani daten e regjistrimit: ");
    scanf("%s", v[count].registrationDate);
    printf("\nShkruani moshen: ");
    scanf("%d", &v[count].age);
    printf("\nRegjistrimi u ruajt me sukses.\n");
    count++;
}

void menu (){
    printf("\nShtyp 1 per te shtuar student.");
    printf("\nShtyp 2 per te shfaqur studentet.");
    printf("\nShtyp 3 per menune.");
    printf("\nShtyp 0 per te mbyllur programin.");
}

void showStudents(){
    if(count == 0){
        printf("\nNuk ka student te regjistruar!\n");
        return;
    }
    for(int i = 0; i < count; i++){ // Fixed loop condition to i < count
        printf("\nStudenti te %d:\n", i+1);
        printf("Emri: %s\n", v[i].name);
        printf("Mbiemri: %s\n", v[i].surname);
        printf("Data e regjistrimit: %s\n", v[i].registrationDate);
        printf("Mosha: %d\n", v[i].age); // Fixed format specifier to %d for int
    }
}

int main(){ // Standard int main()
    printf("*******************PROGRAM PER LIBRARI NE GJUHEN C***********************\n\n");
    menu();
    bool cond = true;
    while(cond){
        int choice;
        printf("\n\nShkruani zgjedhjen tuaj: ");
        scanf("%d", &choice);
        switch(choice){
            case 1:
                addStudents();
                break;
            case 2:
                showStudents();
                break;
            case 3:
                menu();
                break;
            case 0:
                cond = false;
                printf("\nProgrami u mbyll.\n");
                break;
            default:
                printf("\nZgjedhje e pavlefshme! Provoni perseri.\n");
        }
    }
    return 0; // Standard return statement
}

Breakdown of Fixes #

• Loop Condition: Changed i <= count to i < count to only iterate over valid, initialized student entries.
• Age Format Specifier: Swapped %s to %d in the age print line to match the integer type of age.
• Added <stdbool.h>: Required to use the bool type in standard C.
• Standardized main(): Changed to int main() and added return 0; to comply with C standards.
• Removed Unnecessary &: For char arrays like name, scanf("%s", v[count].name) works because arrays decay to pointers—& was redundant here.
• Added Edge Case Handling: If no students are added, showStudents() now prints a friendly message instead of trying to loop over nothing.
• Default Case in Switch: Added a default case to handle invalid input gracefully.

These changes should fix the crash and ensure all students are displayed correctly when you select option 2.

内容的提问来源于stack exchange，提问作者Shpend Palushi