Question

我尝试使用输入中的记录创建一个简单的数据库，并将它们写入文件。但是当我运行程序时，它只适用于第一个记录。我需要说文件已经创建并且写了第一条记录。

#include <stdio.h>

struct produs {
    char nume[20];
    float cantitate,pret_tot,pret_unit;
    };

void main(void) {   
struct produs prod;
int i;
char n;
FILE *fisier;
fisier = fopen("C:\\Users\\amzar\\Desktop\\Programe PC\\Tema suplimentara\\C_3\\tema_c_3\\fisier.txt","w");

printf("\nApasati tasta [d/n] pentru a continua sau nu interogarile!\n");
do {
    printf("\nIntroduceti numele produsului: ");
    fgets(prod.nume,sizeof(prod.nume),stdin);
    scanf("%f\n%f\n%f",&prod.pret_unit,&prod.cantitate,&prod.pret_tot);
    fprintf(fisier,"Numele produsului: %s \nPret unitar: %.2f \nCantitate: %.2f kg \nPret total: %.2f",prod.nume,prod.pret_unit,prod.cantitate,prod.pret_tot);
}  while((n = getche()) != 'n');
fclose(fisier);

}

Answer 1

当您使用getche()时，您的问题就会发生，并且您不会丢弃它在缓冲区上留下的\n。
另请注意，我没有使用fgets在\n中不包含prod.nume。

正确的代码：

#include <stdio.h>

struct produs {
    char nume[20];
    float cantitate, pret_tot, pret_unit;
};

void main(void) {
    struct produs prod;
    int i;
    char n;
    FILE *fisier;
    fisier = fopen("C:\\Users\\amzar\\Desktop\\Programe PC\\Tema suplimentara\\C_3\\tema_c_3\\fisier.txt","w");
    char buffer;

    do {
        printf("\nIntroduceti numele produsului: ");

        /*
          fgets includes the newline character in the string.
          this instruction, instead, exlcudes it (%[^\n]) and discard it (%*c)
        */
        scanf("%[^\n]%*c", prod.nume);
        scanf("%f\n%f\n%f",&prod.pret_unit,&prod.cantitate,&prod.pret_tot);

         //added '\n' at the end of each struct data
        fprintf(fisier,"Numele produsului: %s \nPret unitar: %.2f \nCantitate: %.2f kg \nPret total: %.2f\n",prod.nume,prod.pret_unit,prod.cantitate,prod.pret_tot);

        //input validation for inattentive users
        do{
            //this printf should be before reading the user choice (d/n)
            printf("\nApasati tasta [d/n] pentru a continua sau nu interogarile!\n");

        //here is your error: getche reads the character, but leaves the \n in the buffer...
        }while((n = getche()) != 'n' && n != 'd');

        //...so we have to clean the buffer to not skip next inputs
        scanf("%c", &buffer);
    }while(n == 'd');

    fclose(fisier);

}

来自输入的多个记录不起作用

1 个答案: