代码

int main() {// 定义变量a，赋值为10int a = 10;// 定义变量b，赋值为20int b = 20;// 定义变量c，将a和b相加的结果赋值给cint c = a + b;// 输出c的值printf("%d", c);// 返回0，表示程序正常结束return 0;
}

问题：

vscode中使用code-runner插件允许c程序报错：

[Running] cd "d:\dev\c\study\" && gcc demo1.c -o demo1 && "d:\dev\c\study\"demo1
demo1.c: In function 'main':
demo1.c:9:5: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]9 |     printf("%d", c);|     ^~~~~~
demo1.c:1:1: note: include '<stdio.h>' or provide a declaration of 'printf'+++ |+#include <stdio.h>1 | int main() {
demo1.c:9:5: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]9 |     printf("%d", c);|     ^~~~~~
demo1.c:9:5: note: include '<stdio.h>' or provide a declaration of 'printf'[Done] exited with code=1 in 0.239 seconds

原因

未添加c头文件

#include <stdio.h>