C 程序崩溃... 'Read in and Output Various Data Types'

Question

已更新

我在第 4 章的问题 2 上遇到了一些麻烦，来自 Paul Kelly 的 “C 编程指南”。

据我所知，我的语法是正确的，但是当程序到达第 36 行时，程序会自动填充 scanf(); 变量槽。

我似乎无法在任何地方找到解决这个问题的方法。

这是我的代码。我在第 36 行旁边放了一个标记

---

/* 
   Program to demonstrate single scanf function
   to read various data types and output results.

*/  
#include <stdio.h>

main(){
    int first;
    int second, third, fourth;
    float principle, rate, time;
    char keyVal1, keyVal2;
    char c;
    int i;
    float f;
    double d;

    printf("\nPlease Enter an Integer\n");
    scanf("%d", &first);
    printf("\nYou Entered %d\n", first);

    printf("\nThank You, Please Enter 3 more integers\n");
    scanf("%d %d %d", &second, &third, &fourth);
    printf("\nYou Entered %d %d and %d\n", second, third, fourth);

    printf("\nGreat, 
            now please enter decimal values for principle, 
           rate and time.\n");
    scanf("%f %f %f", &principle, &rate, &time);
    printf("\nYou Entered %.2f %.2f and %.2f\n", principle, rate, time);

    printf("\nPlease Enter any 2 characters\n");
    scanf(" %c %c", &keyVal1, &keyVal2);
    printf("\nYou Entered %c and %c\n", keyVal1, keyVal2); 

    // ***36     
    printf("\nNow Enter any other character, 
            followed by an integer and 2 decimal numbers\n");***
    scanf(" %c %d %f %lf ",&c, &i, &f, &d);
    printf("\nYour character was %c.\nYour integer was %d\nYour 
           decimal numbers were %.2f and %.2lf\n", c, i, f, d);     
} 

Answer 1

scanf("%1s %1s", &keyVal1, &keyVal2);

使用 %c 说明符代替 %1s 。

scanf(" %c %c", &keyVal1, &keyVal2);

同样，

scanf("%c %d %f %lf ",&c, &i, &f, &d); 

在%c前留一个空格-

scanf(" %c %d %f %lf ",&c, &i, &f, &d);

您需要留出空格，因为在 scanf 之后按下 ENTER '\n' 保留在 stdin .