Question

在prompt2函数中，我有两个if语句。首先adder会调用prompt2。当我按'x'或'X'时，为什么它仍然会转到第一个'if'语句，然后打印出来，“Answer is ..”，即使按下x，它应该终止？基本上我想要它，如果你按'x'或'X'，程序就会终止。我也不在main，所以如何从不是main的函数中终止它呢？如果您需要更多代码，我可以编辑，请告诉我。

int prompt2(int sum) {
    char choice; // what the user decides, continuing or not

    printf("\nBefore you continue, take a look at my number guess written down on paper.");
    printf("\nPress 'D' to display the answer or 'X' to exit: " );
    scanf("%c", &choice );

    if ( choice == 'D' || 'd' ) {
        printf("\nAnswer is %d", sum );
    }
    else if ( choice == 'X' || 'x' ) {
        exit(0);

    }


    return 1;

}

int adder( int x, int y ) {

    int sum = 0;

    sum = x + y;
    printf("new sum is %d\n", sum );
    printf(" %d\n+%d\n----\n?", x, y ); // output appropriate line breaks and spacing for equation

    prompt2(sum); // function that asks them if they want to see the answer
    return sum;

}

Answer 1

在if ( choice == 'D' || 'd' )语句中，d不等于零，因此评估为true。它应该是if ( choice == 'D' || choice == 'd' )。

Answer 2

例如，您必须使用if ( choice == 'D' || 'd' )更改此行：if ( choice == 'D' || choice == 'd' )。必须在每个||之后重写变量或者＆amp;＆amp;言。

C逻辑运算符中的程序无法正常工作

2 个答案: