打印#defined'd常数

时间:2012-10-11 16:18:50

标签: c printf c-preprocessor constants literals

#include<stdio.h>

#define UPPER   999999
#define LOWER   11111

int main(void)
{
//  Local Declarations
double price = 89.99;
char grade = 'B';
int age = 97;

//  Statements
printf("Homework 2:\n\nUsing printf\n");
printf("  age = %c, age\n");
printf("grade = %d, grade\n");
printf("price = %f, price\n\n");

printf("Using both printf and scanf\n");
printf("Enter a new value for age: ");
scanf("%d", &age);
printf("Enter a new value for grade: ");
scanf("%c", &grade);
printf("Enter a new value for price: ");
scanf("%lf", &price);

printf("Print the new values\n");
printf("  age = %d \n", age);
printf("grade = %c\n", grade);
printf("price = %lf\n\n", price);

print("\n\nPrinting two defined constants: "UPPER" and "LOWER"\n");
print("UPPER = %08d\n", UPPER);
print("LOWER = %08d\n", LOWER);



return 0;
}   //  end of main

以上是我的程序,我应该修复它。我已经待了将近3个小时,现在仍然可以找出问题所在。我有一个错误和一些警告。

warning: too few arguments for format

中间声明的几个警告

error: expected ')' before numeric constant 

此错误用于打印两个常量。

5 个答案:

答案 0 :(得分:5)

print("\n\nPrinting two defined constants: "UPPER_S" and "LOWER_S"\n");

仅在UPPER_SLOWER_S#define时才有效

#define UPPER_S  "999999"
#define LOWER_S  "11111"

或者,您可以使用以下两个宏来对字符#define进行字符串化:

#define _STRINGIFY(s) #s
#define STRINGIFY(s) _STRINGIFY(s)

然后再做

print("\n\nPrinting two defined constants: "STRINGIFY(UPPER)" and "STRINGIFY(LOWER)"\n");

答案 1 :(得分:4)

我来到这里寻找这个问题的答案,似乎大多数人只是挂了语法错误,而不是关心实际问题是什么。您可以将printf与#define d值一起使用,就像它们是正常变量一样。但是你必须密切注意类型。

#define HEXNUM 0xA8
#define NUMBER 129
#define STRING "somestring"

#include <stdio.h>

int main(void) {
    printf("hex number: %x\n", HEXNUM);
    printf("number: %d\n", NUMBER);
    printf("string: %s", STRING);

    return 0;
}

答案 2 :(得分:2)

这样的事情
printf("grade = %d, grade\n");

期待'%d'的参数。它应该是

的形式
printf("grade = %d\n", grade);

答案 3 :(得分:1)

你需要把你的printf args放在引号之外。

电流:

//  Statements
printf("Homework 2:\n\nUsing printf\n");
printf("  age = %c, age\n");
printf("grade = %d, grade\n");
printf("price = %f, price\n\n");

应该是:

//  Statements
printf("Homework 2:\n\nUsing printf\n");
printf("  age = %c\n", age);
printf("grade = %d\n", grade);
printf("price = %f\n\n", price);

答案 4 :(得分:1)

一种方法是将常量定义的变量值分配给局部变量值。这样它在printf中很有用(&#34;%d&#34;,X);方法

但是,您可以使用const int EXAMPLE = 12,然后可以在标准printf方法中使用EXAMPLE,例如, printf(&#34;%d \ n&#34;,示例);