Trying to use 'system()' and 'execv()' function calls - c

Question

I want to execute a C program from another C program. Actually I need to use system() function for my functionality as the control returns to the calling program. As I was not able to get the result with system(), I tried using execv() which was not successful either.
Below are the sample codes which I was trying
int main(void) {
puts("executing this prog from another prog");
return EXIT_SUCCESS;
}
The above one is called test1.c
int main(void) {
execv("./test1",NULL); //system("./test1");
puts("!!!Hello World!!!");
return EXIT_SUCCESS;
}
This is test2.c
With system(), I am getting the sh: 1: ./test1: not found error and with execv() its just ignoring the statement and printing the !!!Hello World!!!
Note : Mainly I want to know the functioning of system() for the problem I want to solve.

Answer 1

The second parameter of execv must be an array of pointers to null-terminated strings, change to:
#include <unistd.h>
int main(void)
{
char *argv[] = {NULL};
execv("./test1", argv);
return 0;
}
If this fails you can check the cause of the error with perror:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main(void)
{
char *argv[] = {NULL};
if (execv("./test1", argv) == -1) {
perror("execv");
exit(EXIT_FAILURE);
}
return 0;
}