Fork and have childs do different tasks

int main ( ) {
    // code goes here
}

$ gcc -Wall foo.c
foo.c: In function ‘main’:
foo.c:55:7: warning: implicit declaration of function ‘wait’ [-Wimplicit-function-declaration]
foo.c:13:12: warning: unused variable ‘pos’ [-Wunused-variable]
foo.c:11:9: warning: unused variable ‘end’ [-Wunused-variable]
foo.c:61:1: warning: control reaches end of non-void function [-Wreturn-type]

$ gcc -Wall foo.c
foo.c: In function ‘main’:
foo.c:57:7: error: incompatible type for argument 1 of ‘wait’
/usr/include/x86_64-linux-gnu/sys/wait.h:116:16: note: expected ‘__WAIT_STATUS’ but argument is of type ‘int’
foo.c:57:7: error: too many arguments to function ‘wait’
/usr/include/x86_64-linux-gnu/sys/wait.h:116:16: note: declared here
foo.c:15:12: warning: unused variable ‘pos’ [-Wunused-variable]
foo.c:13:9: warning: unused variable ‘end’ [-Wunused-variable]
foo.c:63:1: warning: control reaches end of non-void function [-Wreturn-type]

$ ./a.out 
I am child 4034 and my parent is 4033
Parent done waiting for 4034, found 4034
I am child 4035 and my parent is 4033
Parent done waiting for 4035, found 4035
I am child 4036 and my parent is 4033
Parent done waiting for 4036, found 4036
I am child 4037 and my parent is 4033
Parent done waiting for 4037, found 4037
I am child 4038 and my parent is 4033
Parent done waiting for 4038, found 4038


#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

int main(){
  long int i, j;
  int pid;
  int rows, columns;
  FILE *input;
  int number;
  pid_t end;
  int temp;
  int total = 0;
  FILE *output;

  rows = 5;
  columns = 5;
  output = fopen("input.dat", "w");
  fprintf(output,"%d %d\n", rows, columns);
  for (i = 0; i < rows; i++){
    for (j = 0; j < columns; j++){
      fprintf(output, "%d ", 1 + rand() % 9);
    }
    fprintf(output, "\n");
  }
  fclose(output);

  input = fopen("input.dat", "r");
  fscanf(input,"%d %d", &rows, &columns);

  for (i = 0; i < rows; i++){
    pid = fork();
    if (pid == 0){
      printf("I am child %d and my parent is %d\n", getpid(), getppid());
      fseek(input, i*columns*2, SEEK_CUR);
      for (j = 0; j < columns; j++){
        fscanf(input, "%d", &number);
        total = total + number;
      }
      output = fopen("output.dat", "a+");
      fprintf(output,"Child %ld sum is = %d\n", i+1,total);
      fclose(output);
      exit(0);
      sleep(1);
    }

    else if (pid == -1){
      perror("Fork error");
    }

    else {
      sleep(1);
      end = waitpid(-1, &temp,0);
      printf("Parent done waiting for %d, found %d\n", pid, end );
    }
  }

  fclose(input);
  return 0;
}