How to write a code in C language to output the absolute value?

You can use the abs function in C language to calculate absolute value. The prototype of the abs function is as follows:

int abs(int n);

The example code is shown below:

#include <stdio.h>
#include <stdlib.h>

int main() {
    int num;
    printf("请输入一个整数：");
    scanf("%d", &num);

    int absNum = abs(num);
    printf("绝对值为：%d\n", absNum);

    return 0;
}

In the above code, we utilized the abs function to calculate the absolute value of the input integer and the printf function to display the result.