UCSD CSE29 Fall 2024

Other Helpful Functions

This PA explores several features that are straightforward to use, but there are many of them. We might add more to this list as the PA goes on! Here are a few functions you'll probably find useful; try man on them, or follow the links, or do your own searching and research. Don't forget all the functions from class (e.g. malloc and other allocation functions, strstr and other string manipulation functions, and so on). This list is mainly focused on things we haven't tried in class.

• atoi: convert char* to integer

  For example:

  #include <stdio.h>
  #include <stdlib.h>
  
  int main() {
    char numeric[] = "123";
    int asnum = atoi(numeric);
    printf("%d\n", asnum * 2);
  }
  

• Time functions:

  • time: get the current time

  • localtime: convert the time to the current local time zone

  • strftime: print the time in a given format

    For example:

    #include <time.h>
    #include <stdio.h>
    
    int main() {
        char buffer[100];
        time_t now = time(NULL);
        struct tm *tm_info = localtime(&now);
        strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", tm_info);
        printf("%s", buffer);
    }