Question

#include <stdio.h>


int multiple(int num1,int num2){
    return (num1*num2);
}

int add(int num1, int num2){
    return (num1+num2);
}
/*&x points to its value space *x points to its memory space*/
int main(){

    int num1,num2,ans;
    char func;

    printf("First number => ");
    scanf("%d",&num1);
    printf("Second number => ");
    scanf("%d",&num2);

    printf("Please Enter + for addition, or * for multiplication => ");
    scanf("%c",&func);

    if (func == '*'){
        ans = multiple(num1,num2);
    }else if(func == '+') {
        ans = add(num1,num2);
    }else {
        printf("Sorry, invalid operation");
    }

    printf("Ans : %d",ans);
    return 0;
}

当我运行我的程序时，它会提示我进行firest和第二个数字但是它不会让我输入scanf("%c",&func);没有被执行。

我的输出--------------------------------------------- --------------------：

$ ./p8t3 First number => 23 Second number => 32 Please Enter + for addition, or * for multiplication => Sorry, invalid operationAns : 2665616

Answer 1

在扫描+或*运算符时，更改如下：

printf("Please Enter + for addition, or * for multiplication => ");
scanf(" %c",&func);         //use a space before '%c'

Answer 2

printf("Please Enter + for addition, or * for multiplication => ");
scanf(" %c",&func);

原因是当您输入数字并按ENTER时，scanf将处理该数字，但新行仍在输入缓冲区中。

当使用scanf作为整数以及char值时，程序会跳过scanf

2 个答案: