我从这段代码中得到了一些内存泄漏，而且我对c很缺乏经验。下面是泄漏内存的代码，下面是valgrind输出。我似乎无法缩小未被释放的确切内存块，请帮忙！很抱歉代码重载，我是新来的。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "students.h"
void init_student(struct student* student, char* name, int id, float gpa) {
int name_size = strlen(name);
student->name = malloc(sizeof(char) * (name_size + 1));
strcpy(student->name, name);
student->id = id;
student->gpa = gpa;
}
void free_student(struct student* student) {
free(student->name);
}
struct student* deep_copy_student(struct student* student) {
struct student *copy;
copy = (struct student*) malloc(sizeof(struct student));
init_student(copy, student->name, student->id, student->gpa);
return copy;
}
struct student* create_student_array(int num_students, char** names, int* ids,
float* gpas) {
struct student* students;
students = malloc(sizeof(struct student) * num_students);
for (int i = 0; i < num_students; ++i) {
init_student(&students[i], names[i], ids[i], gpas[i]);
}
return students;
}
void destroy_student_array(struct student* students, int num_students) {
for (int i = 0; i > num_students; i++) {
free_student(&students[i]);
}
free(students);
}
void print_students(struct student* students, int num_students) {
for (int i=0; i < num_students; ++i) {
printf("Name: %s, ID: %d, GPA: %f\n" , students[i].name, students[i].id, students[i].gpa);
}
}
struct student* find_max_gpa(struct student* students, int num_students) {
struct student* best_in_school;
best_in_school = &students[0];
for (int i = 1; i < num_students; ++i) {
if(students[i].gpa > best_in_school->gpa){
best_in_school = &students[i];
}
}
return best_in_school;
}
struct student* find_min_gpa(struct student* students, int num_students) {
struct student* worst_in_school;
worst_in_school = &students[0];
for (int i = 1; i < num_students; ++i) {
if(students[i].gpa < worst_in_school->gpa){
worst_in_school = &students[i];
}
}
return worst_in_school;
}
void sort_by_gpa(struct student* students, int num_students) {
struct student temp;
for (int i = 0; i < (num_students - 1); ++i) {
for (int j = 0; j < (num_students - i); ++j) {
if(students[j].gpa < students[j+1].gpa) {
temp = students[j];
students[j] = students[j+1];
students[j+1] = temp;
}
}
}
}
test.c只是一个测试所有功能的框架，是预制的，所以不是问题。它似乎源自前面代码中制作的8名学生。
==31704== HEAP SUMMARY:
==31704== in use at exit: 88 bytes in 8 blocks
==31704== total heap usage: 12 allocs, 4 frees, 262 bytes allocated
==31704==
==31704== 88 bytes in 8 blocks are definitely lost in loss record 1 of 1
==31704== at 0x4C29BE3: malloc (vg_replace_malloc.c:299)
==31704== by 0x40092C: init_student (students.c:50)
==31704== by 0x400A66: create_student_array (students.c:133)
==31704== by 0x4007B5: main (test.c:92)
==31704==
==31704== LEAK SUMMARY:
==31704== definitely lost: 88 bytes in 8 blocks
==31704== indirectly lost: 0 bytes in 0 blocks
==31704== possibly lost: 0 bytes in 0 blocks
==31704== still reachable: 0 bytes in 0 blocks
==31704== suppressed: 0 bytes in 0 blocks
==31704==
==31704== For counts of detected and suppressed errors, rerun with: -v
==31704== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
这是主文件。就像我之前说的那样，它只是为我提供的测试台。希望它有所帮助。
#include <stdio.h>
#include <stdlib.h>
#include "students.h"
/*
* This is the total number of students in the testing data set.
*/
#define NUM_TESTING_STUDENTS 8
/*
* These are the names of the students that'll be used for testing.
*/
char* TESTING_NAMES[] = {
"Luke Skywalker",
"Princes Leia",
"Chewbacca",
"Han Solo",
"Lando Calrissian",
"Darth Vader",
"C-3PO",
"R2-D2"
};
/*
* These are the student IDs for the students in the array above that will be
* used for testing.
*/
int TESTING_IDS[] = {
933111111,
933222222,
933333333,
933444444,
933555555,
933666666,
933777777,
933888888
};
/*
* These are the GPAs of the students above that will be used for testing.
*/
float TESTING_GPAS[] = {
3.75,
4.0,
3.0,
2.5,
3.67,
1.33,
3.25,
3.9
};
int main(int argc, char** argv) {
struct student student;
struct student* copy = NULL, * max_gpa, * min_gpa, * students = NULL;
int i;
/*
* Initialize a student using init_student() and print the results. The
* power of pointers lets us use print_students() this way!
*/
init_student(&student, TESTING_NAMES[0], TESTING_IDS[0], TESTING_GPAS[0]);
printf("\n== Here are the results of init_student():\n");
print_students(&student, 1);
/*
* Make a copy of student using deep_copy_student() and compare the results.
*/
copy = deep_copy_student(&student);
printf("\n== Here's that student (left) and its deep copy (right):\n");
if (copy) {
printf("name (value): %s\t%s\n", student.name, copy->name);
printf("name (pointer): %p\t%p\n", student.name, copy->name);
printf("id: %d\t%d\n", student.id, copy->id);
printf("gpa: %f\t%f\n", student.gpa, copy->gpa);
}
/*
* Create an array of students using create_student_array() and print the
* results.
*/
students = create_student_array(NUM_TESTING_STUDENTS, TESTING_NAMES,
TESTING_IDS, TESTING_GPAS);
printf("\n== Here are the results of create_student_array():\n");
print_students(students, NUM_TESTING_STUDENTS);
/*
* Use find_max_gpa() to find the student with the highest GPA and print
* the result.
*/
max_gpa = find_max_gpa(students, NUM_TESTING_STUDENTS);
printf("\n== Here's the student with the highest GPA:\n");
print_students(max_gpa, 1);
/*
* Use find_min_gpa() to find the student with the lowest GPA and print
* the result.
*/
min_gpa = find_min_gpa(students, NUM_TESTING_STUDENTS);
printf("\n== Here's the student with the lowest GPA:\n");
print_students(min_gpa, 1);
/*
* Use sort_by_gpa() to order the students by decreasing GPA and print the
* results.
*/
sort_by_gpa(students, NUM_TESTING_STUDENTS);
printf("\n== Here are the students ordered by decreasing GPA:\n");
print_students(students, NUM_TESTING_STUDENTS);
/*
* Free all of the memory we allocated here. You should use valgrind to
* verify that you don't have memory leaks.
*/
free_student(&student);
free_student(copy);
free(copy);
destroy_student_array(students, NUM_TESTING_STUDENTS);
return 0;
}
答案 0 :(得分：6)
在for函数中将i > num_students结束表达式从i < num_students更改为destroy_student_array。循环永远不会进入正数学生 - 这可能是泄漏的来源。