斯堪夫和斯特托克不适合我
我试着写一个基于菜单的小程序来保存记录。用户输入要存储的总人数(名、姓、分数)所用的数字。用户在一行中输入所有信息，用空格分隔，我将它们分成3列(名字、姓氏、分数)，然后按enter键，然后继续输入更多信息，直到最大用户被击中为止。
我的问题是，当我运行它时，它不能正常工作；它运行并接受用户输入，但只对两个学生(即使我在测试用例中使用大于5的数字)，然后程序立即结束(没有错误代码，只是结束.)甚至连菜单上都没有。有人能告诉我我的密码出了什么问题吗？
int i, j, count, numberPeople, temp, choice;
char people[15][3], tempArr[20];
char *token;
printf("Please indicate number of records you want to enter (min 5, max 15): ");
scanf("%d", &temp);
while ((temp > 15) || (temp < 5)) {
printf("\nNumber not in specified range, try again.\n");
printf("Please indicate number of records you want to enter (min 5, max 15): ");
scanf("%d", &temp);
}
numberPeople = temp;
printf("\nEnter the first name, last name, and grade (put a space in between each): ");
for (i = 0; i < numberPeople; i++) {
fgets(tempArr, 20, stdin);
token = strtok(tempArr, " ");
for (j = 0; j < 3; j++) {
while (token != NULL) {
people[i][j] = *token;
printf("%s\n", token); // this is here to as a test case to see if my data was being stored.
token = strtok(NULL, " ");
}
}
}编辑:将scanf更改为fget
输出
Please indicate number of records you want to enter (min 5, max 15): 5
Enter the first name, last name, and grade (put a space in between each): firstname1 lastname1 85
firstname1
lastname1
85
firstname2 lastname2 84
firstname2
lastname2
Program ended with exit code: 0回答 3
Stack Overflow用户
发布于 2016-03-23 20:54:34
一个问题是，您正在使用scanf()读取整个输入行，该输入行在名字、姓氏和等级之间有空格：
for (i = 0; i < numberPeople; i++) {
scanf("%s", tempArr);
}scanf("%s", tempArr)一到达第一个空格就退出阅读。对于这个循环，您要使用fgets()
for (i = 0; i < numberPeople; i++) {
fgets(tempArr, 20, stdin);
}但正如@Pooya所指出的，这个字符串的大小对于您所做的工作来说太小了。虽然您分配了学生和信息字段的二维数组，但从未分配字符串空间来保存他们的姓名和年级：
char people[15][3]如果在堆栈上执行此操作，则在概念上成为第三个维度：
char people[15][3][24]在这个scanf()之后，缓冲区中仍然保留一个返回字符：
scanf("%d", &temp);可能应该清空了。@KevinDTimm和@bruceg在这里暗示了一个问题：
for (j = 0; j < 3; j++) {
while (token != NULL) {
people[i][j] = *token;但我不认为Kevin的建议说明了j. @Weather_Vane建议在strtok()分隔符字符串中添加\r\n：
token = strtok(NULL, " ")否则，您的等级字符串(最后一个字段)将有一个悬空的换行符。另外，您需要复制strtok()返回的令牌，不应该直接存储它。
将所有这些建议结合起来，并清理/修复我遇到的其他任何东西，我提供以下重做：
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MINIMUM_STUDENTS 5
#define MAXIMUM_STUDENTS 15
#define DATA_FIELDS 3
#define MAXIMUM_LINE_LENGTH 100
#define MAXIMUM_DATA_LENGTH 50
int main(int argc, char **argv) {
int numberPeople;
char people[MAXIMUM_STUDENTS][DATA_FIELDS][MAXIMUM_DATA_LENGTH];
printf("Please indicate number of records you want to enter (min %d, max %d): ", MINIMUM_STUDENTS, MAXIMUM_STUDENTS);
scanf("%d", &numberPeople);
while ((numberPeople < MINIMUM_STUDENTS) || (numberPeople > MAXIMUM_STUDENTS)) {
printf("\nNumber not in specified range, try again.\n");
printf("Please indicate number of records you want to enter (min %d, max %d): ", MINIMUM_STUDENTS, MAXIMUM_STUDENTS);
scanf("%d", &numberPeople);
}
printf("\n");
while ((getchar()) != '\n'); // flush the return (and anything else) after the number input above
printf("Enter the first name, last name, and grade (put a space in between each): \n");
for (int i = 0; i < numberPeople; i++) {
char tempArr[MAXIMUM_LINE_LENGTH];
fgets(tempArr, MAXIMUM_LINE_LENGTH, stdin);
char *token = strtok(tempArr, " ");
for (int j = 0; j < DATA_FIELDS && token != NULL; j++) {
strncpy(people[i][j], token, MAXIMUM_DATA_LENGTH);
// this is here to as a test case to see if my data was being stored.
printf("%s\n", people[i][j]);
token = strtok(NULL, " \r\n");
}
}
// do what you need to do with the data here!
return 0;
}Stack Overflow用户
发布于 2016-03-23 20:54:10
首先，使用fgets()而不是scanf()
接下来，您不需要由strtok处理的for strtok部件。相反，请使用以下内容：
token = strtok(tempArr, " ");
while (token != NULL) {
people[i][j] = *token;
printf("%s\n", token); // this is here to as a test case to see if my data was being stored.
token = strtok(NULL, " ");
}Stack Overflow用户
发布于 2016-03-23 20:56:32
根据您的示例，您的输入是关于24字符的，但是定义了tempArr[20]。因为如果扫描的不是20字符，而是覆盖内存中的其他内容，所以最好有tempArr[100]或对测试有意义的任何数字。
https://stackoverflow.com/questions/36188318
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