How to achieve the rounding of a number to one decimal …

In the C language, you can use the standard library function round() to achieve rounding to the nearest whole number while preserving one decimal point. The prototype of the round() function is as follows:

double round(double x);

The round() function rounds the parameter x to the nearest integer and returns the result. To keep one decimal place, you can multiply the number by 10, pass the result to the round() function for rounding, and then divide by 10 to get the result with one decimal place.

Here is an example code:

#include <stdio.h>
#include <math.h>

int main() {
    double num = 3.14; // 要四舍五入的数
    double result = round(num * 10) / 10; // 四舍五入并保留一位小数

    printf("原始数：%.2f\n", num);
    printf("四舍五入保留一位小数：%.1f\n", result);

    return 0;
}

The output/result of the operation is:

原始数：3.14
四舍五入保留一位小数：3.1

In this example, the original number is 3.14, and after rounding to one decimal place, it becomes 3.1.