#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAX_STUDENTS 100
struct student {
char name[50];
int reg_no;
char programme[50];
char school[50];
float cgpa;
int rank;
};
int main() {
FILE *fp, *mp;
char line[200];
int num_students = 0;
struct student students[MAX_STUDENTS];
int num_failures = 0;
// open student details file for reading
fp = fopen("student_details.txt", "r");
if (fp == NULL) {
// file does not exist, create it
fp = fopen("student_details.txt", "w");
if (fp == NULL) {
printf("Error: could not create file\n");
return 1;
}
} else {
// read data from file and store in array
while (fgets(line, sizeof(line), fp)) {
sscanf(line, "%[^,], %d, %[^,], %[^,], %f, %d",
students[num_students].name,
&students[num_students].reg_no,
students[num_students].programme,
students[num_students].school,
&students[num_students].cgpa,
&students[num_students].rank);
num_students++;
}
}
// close student details file
fclose(fp);
// sort array by CGPA (descending order)
for (int i = 0; i < num_students - 1; i++) {
for (int j = i + 1; j < num_students; j++) {
if (students[i].cgpa < students[j].cgpa) {
// swap students i and j
struct student temp = students[i];
students[i] = students[j];
students[j] = temp;
}
}
}
// update ranks based on sorted order
for (int i = 0; i < num_students; i++) {
students[i].rank = i + 1;
}
// open student details file for writing
fp = fopen("student_details.txt", "w");
// write updated data to file
for (int i = 0; i < num_students; i++) {
fprintf(fp, "%s, %d, %s, %s, %f, %d\n",
students[i].name,
students[i].reg_no,
students[i].programme,
students[i].school,
students[i].cgpa,
students[i].rank);
if (students[i].cgpa < 4.0) {
// student has failed
num_failures++;
if (num_failures == 1) {
// open monitor file for writing
mp = fopen("monitor.txt", "w");
fprintf(mp, "Students who scored less than 4.0 CGPA:\n");
}
fprintf(mp, "%s, %d, %s, %s, %f, %d\n",
students[i].name,
students[i].reg_no,
students[i].programme,
students[i].school,
students[i].cgpa,
students[i].rank);
}
}
// close files
fclose(fp);
if (num_failures > 0) {
fclose(mp);
printf("Ranking has been updated and saved to student_details.txt\n");
printf("%d student(s) failed\n", num_failures);
printf("Details of students who failed have been saved to monitor.txt\n");
} else {
printf("Ranking has been updated and saved to student_details.txt\n");
printf("All students passed\n");
}
return 0;
}
Write, Run & Share C Language code online using OneCompiler's C online compiler for free. It's one of the robust, feature-rich online compilers for C language, running the latest C version which is C18. Getting started with the OneCompiler's C editor is really simple and pretty fast. The editor shows sample boilerplate code when you choose language as 'C' and start coding!
OneCompiler's C online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample C program which takes name as input and print your name with hello.
#include <stdio.h>
int main()
{
char name[50];
printf("Enter name:");
scanf("%s", name);
printf("Hello %s \n" , name );
return 0;
}
C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.
When ever you want to perform a set of operations based on a condition if-else is used.
if(conditional-expression) {
// code
} else {
// code
}
You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to if-else-if ladder.
switch(conditional-expression) {
case value1:
// code
break; // optional
case value2:
// code
break; // optional
...
default:
// code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement){
// code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while(condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.
data-type array-name[size];
data-type array-name[size][size];
Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.
Two types of functions are present in C
Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,
User defined functions are the ones which are written by the programmer based on the requirement.
return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
//code
}