Ç - 警告：函数'printf“式的隐式声明 [英] c - warning: implicit declaration of function ‘printf’

问题描述

我知道有很多类似的问题以前问过，但我无法找到的东西，会解决这个警告，我得到：

I know alot of similar questions were asked before but i couldn't find something that would fix this warning i get:

MyIntFunctions.c:19:2: warning: implicit declaration of function ‘printf’ [-Wimplicit-function-declaration]

在这里发生：

void IntPrint (const void *key)
{
    printf("%d", *(int*)key); // line 19
    printf("\t-->\t");
}

和类似的警告：

MyStringFunctions.c:22:2: warning: implicit declaration of function ‘printf’ [-Wimplicit-function-declaration]

void StringPrint (const void *key)
{
    printf("%s",(char*)key); //line 22
    printf("\t-->\t");
}

我真的想了解什么是错的，所以我不会在将来再次做到这一点。

I really want to understand what is wrong so i won't do that again in the future.

推荐答案

您需要包括相应的​​头

You need to include the appropriate header

#include <stdio.h>

如果你不知道这头一个标准功能是，该功能的手册页中定义会说明这一点。

If you're not sure which header a standard function is defined in, the function's man page will state this.

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