memory.c

current ram used in percent

#include <stdio.h>

int main(void) {
 
  FILE* fp = fopen("/proc/meminfo", "r");
  
  if (fp != NULL) {
    char buf[128];
    int total, avail;
    
    while (fgets(buf, 128, fp)) {
      if (sscanf(buf, "MemTotal: %d", &total)) {
        continue;
      }
      if (sscanf(buf, "MemAvailable: %d", &avail)) {
        break;
      }
    }

    fclose(fp);

    float used = (total - avail) / (float) total * 100;

    printf("%.0f%%\n", used);
  }
}