尝试在Codeblocks中编译时出现以下错误：
main.c|94|error: expected expression before '==' token|
main.c|99|error: expected expression before '==' token|
main.c|100|error: 'title' undeclared (first use in this function)|
main.c|100|note: each undeclared identifier is reported only once for each function it appears in|
main.c|119|error: incompatible types when assigning to type 'char[3]' from type 'char *'|
main.c|133|error: expected expression before '==' token|
main.c|138|error: expected expression before '==' token|
main.c|159|error: incompatible types when assigning to type 'char[3]' from type 'char *'|
main.c|188|error: expected expression before 'int'|
main.c|201|error: expected expression before '==' token|
main.c|206|error: expected expression before '==' token|
||=== Build failed: 10 error(s), 0 warning(s) (0 minute(s), 0 second(s)) ===|
这是我的代码。
#include <stdio.h>
#include <ctype.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#define LENGTH == 30;
typedef struct {
char div[3];
short dept, num;
char credits[3];
char title[30];
} course;
int main()
{
printf("Welcome to the Ultimate Course Database App!\n");
int input;
char filenameOne[20];
char filenameTwo[20];
printf("Please type in the name of the database file:\n");
scanf("%s", &filenameOne);
FILE *in_file = fopen(filenameOne, "r");
//If the file does not exist
if (!in_file)
{
printf("The file you entered does not exist. A new file with the same name will be created for you.\n");
//Create the file
FILE *in_file = fopen(filenameOne, "w");
course Course;
for (int counter=0; counter <= 559999; counter++)
{
Course.dept == 000;
Course.num == 000;
fwrite(&Course, sizeof(course), 1, in_file);
}
}
do
{
fseek(in_file, 0, SEEK_SET);
printf("Please choose from the options below, by typing in the corresponding number.\n");
printf("1: Create new courses from a plain text file, adding them to the database.\n");
printf("2: Add a single course to the database.\n");
printf("3: Display all the details of a particular course.\n");
printf("4: Display all the actual courses in the database.\n");
printf("5: Change the name of a course in the database.\n");
printf("6: Delete a course from the database.\n");
printf("7: Add a course to a semester course listing.\n");
printf("8: Remove a course from a semester course listing.\n");
printf("9: Display a semester course listing, in course number order.\n");
printf("10: Quit.\n");
scanf("%d", &input);
//If Option 1 is selected
if (input == 1) {
printf("You selected Option 1: Create new courses from a plain text file, adding them to the database.\n");
printf("Please type in the name of your text file below.\n");
scanf("%s", &filenameTwo);
FILE *in_file_text = fopen(filenameTwo, "r");
if (!in_file_text) {
fprintf(stderr, "File not found.\n");
}
while (feof(in_file_text)) {
//Joanne's code
int c1, c2;
char div[3], title[LENGTH+1];
int dept, num;
int count = 0;
int c = ' ';
fscanf(in_file_text, "%2s.%d.%d %d.%d ", div, &dept, &num, &c1, &c2);
while (count < LENGTH && (c = fgetc(in_file_text)) != '\n') {
title[count++] = (char) c;
}
title[count] = '\0';
while (c != '\n') c = fgetc(in_file_text);
//error checking
if (!(dept<701 && dept>001 && num<899 && num>100 && (c1 == 0 || c1 == 1 || c1 == 5) && (c2 == 0 || c2 == 1 || c2 == 5))) {
fprintf(stderr, "Invalid input.\n");
}
course ToVerify;
fseek(in_file, ((dept)*700)+(num-100), SEEK_SET);
fread(&ToVerify, sizeof(course), 1, in_file);
//check to see if empty course or not
if (ToVerify.dept == 000 && ToVerify.num == 000) {
course ToAdd;
ToAdd.dept = dept;
ToAdd.num = num;
ToAdd.div = div;
ToAdd.title = title;
fwrite(&ToAdd, sizeof(course), 1, in_file);
}
}
fclose(in_file_text);
}
//If option 2 is selected
if (input == 2) {
printf("You selected Option 2: Add a single course to the database.\n");
printf("Please type in the course below.\n");
//Joanne's code
int c1, c2;
char div[3], title[LENGTH+1];
int dept, num;
int count = 0;
int c = ' ';
fscanf(stdin, "%2s.%d.%d %d.%d ", div, &dept, &num, &c1, &c2);
while (count < LENGTH && (c = fgetc(stdin)) != '\n') {
title[count++] = (char) c;
}
title[count] = '\0';
while (c != '\n') c = fgetc(stdin);
//do the whole thing from 1 all over again
//error checking
if (!(dept<701 && dept>001 && num<899 && num>100 && (c1 == 0 || c1 == 1 || c1 == 5) && (c2 == 0 || c2 == 1 || c2 == 5))) {
fprintf(stderr, "Invalid input.\n");
}
course ToVerify;
fseek(in_file, ((dept)*700)+(num-100), SEEK_SET);
fread(&ToVerify, sizeof(course), 1, in_file);
//check to see if empty course or not
if (ToVerify.dept == 000 && ToVerify.num == 000) {
course ToAdd;
ToAdd.dept = dept;
ToAdd.num = num;
ToAdd.div = div;
ToAdd.title = title;
fwrite(&ToAdd, sizeof(course), 1, in_file);
}
}
//If option 3 is selected
if (input == 3) {
printf("You selected Option 3: Display all the details of a particular course.\n");
printf("Please type in the department and course number below.\n");
int dept, num;
fscanf(stdin, "%d.%d", &dept, &num);
// check for input error
if (!(dept<701 && dept>001 && num<899 && num>100)) {
fprintf(stderr, "Invalid input.\n");
}
course ToDisplay;
fseek(in_file, ((dept)*700)+(num-100), SEEK_SET);
fread(&ToDisplay, sizeof(course), 1, in_file);
printf("%2s.%d.%d %d.%d ", ToDisplay.div, ToDisplay.dept, ToDisplay.num, ToDisplay.credits, ToDisplay.title);
}
//If Option 4 is selected
if (input == 4) {
printf("You selected Option 4: Display all courses.\n");
while (int counter = 0, counter < 560000, counter++) {
course ToDisplay;
fread(&ToDisplay, sizeof(course), 1, in_file);
if (ToDisplay.dept != 000 && ToDisplay.num != 000) {
printf("%2s.%d.%d %d.%d ", ToDisplay.div, ToDisplay.dept, ToDisplay.num, ToDisplay.credits, ToDisplay.title);
}
}
}
//If option 5 is selected
if (input == 5) {
printf("You selected Option 5: Change the name of a course.\n");
printf("Please type in the department and course number below, with the new name\n");
char title[LENGTH+1];
int dept, num;
int count = 0;
int c = ' ';
fscanf(stdin, "%2s.%d.%d", div, &dept, &num);
while (count < LENGTH && (c = fgetc(fp)) != '\n') {
title[count++] = (char) c;
}
title[count] = '\0';
while (c != '\n') c = fgetc(stdin);
//check for input error DO
if (!(dept<701 && dept>001 && num<899 && num>100)) {
fprintf(stderr, "Invalid input.\n");
}
course ToChange;
fseek(in_file, ((dept)*700)+(num-100), SEEK_SET);
fread(&ToChange, sizeof(course), 1, in_file);
if (ToChange.dept != 000 && ToChange.num != 000) {
ToChange.title = title;
fwrite(&ToChange, sizeof(course), 1, in_file);
}
if (ToChange.dept == 000 && ToChange.num == 000) {
fprintf(stderr, "Record id empty!");
}
}
//If Option 6 is selected
if (input == 6) {
printf("You selected Option 6: Delete a course.\n");
printf("Please type in the department and course number below.\n");
int dept, num;
fscanf(stdin, "%d.%d", &dept, &num);
//check for input error DO
if (!(dept<701 && dept>001 && num<899 && num>100)) {
fprintf(stderr, "Invalid input.\n");
}
course ToDelete;
fseek(in_file, ((dept)*700)+(num-100), SEEK_SET);
fread(&ToDelete, sizeof(course), 1, in_file);
if (ToDelete.dept != 000 && ToDelete.num != 000) {
ToDelete.dept == 000;
ToDelete.num == 000;
ToDelete.div == "";
ToDelete.credits == "";
ToDelete.title == "";
fwrite(&ToDelete, sizeof(course), 1, in_file);
}
if (ToDelete.dept == 000 && ToDelete.num == 000) {
fprintf(stderr, "Record id empty!\n");
}
}
}
while (input < 10);
fclose(in_file);
}
答案 0 :(得分：1)
define语法不正确，正确的语法是：
#define LENGTH 30
这里有=和==不匹配：
Course.dept = 000;
Course.num = 000;
您使用的是C99吗？除非是这种情况，否则for循环中的声明是错误的：
for (int counter=0; counter <= 559999; counter++)
不要使用= here：
指定静态字符[X]ToAdd.div = div;
ToAdd.title = title;
strcpy或strncpy或直接将char写入struct字段。
for循环的循环instrad格式错误（C99语法）：
while (int counter = 0, counter < 560000, counter++) {
fp变量在这里未知：
while (count < LENGTH && (c = fgetc(fp)) != '\n') {
尝试构建以逐步编写代码并编译它以尽快检测每个错误。一旦解决了#define，每个错误都会显示其行，您只需构建，修复第一个错误，构建，修复第二个错误等等：
In function ‘main’:
101:31: error: incompatible types when assigning to type ‘char[3]’ from type ‘char *’
102:33: error: incompatible types when assigning to type ‘char[30]’ from type ‘char *’
141:27: error: incompatible types when assigning to type ‘char[3]’ from type ‘char *’
142:29: error: incompatible types when assigning to type ‘char[30]’ from type ‘char *’
167:20: error: expected expression before ‘int’
185:49: error: ‘fp’ undeclared (first use in this function)
185:49: note: each undeclared identifier is reported only once for each function it appears in
200:32: error: incompatible types when assigning to type ‘char[30]’ from type ‘char *’
之后你必须测试你的程序。