Measure C Program Execution Time

In the C language, the program’s running time can be measured using the clock() function in the time.h header file. The specific steps are as follows:

1. Firstly, the time.h header file needs to be included.

#include <time.h>

1. Call the clock() function at the beginning of the program to obtain the clock time when the program starts executing.

clock_t start = clock();

1. Call the clock() function at the end of the program to obtain the clock time when the program finishes execution.

clock_t end = clock();

1. Calculate the running time of the program. The clock() function returns the number of clock cycles, which need to be divided by CLOCKS_PER_SEC to get the running time in seconds.

double elapsed_time = (double)(end - start) / CLOCKS_PER_SEC;

The complete example code is as follows:

#include <stdio.h>
#include <time.h>

int main() {
    clock_t start = clock();
    
    // 程序逻辑代码
    
    clock_t end = clock();
    double elapsed_time = (double)(end - start) / CLOCKS_PER_SEC;
    
    printf("程序运行时间：%f秒\n", elapsed_time);
    
    return 0;
}

The above code will output the program’s running time in seconds.