I making a program in C.

I want to read a file using "od -c" command, I was trying to use exec
for the same.

But I don't have much idea about exec. Can anyone suggest how to use
for od command and also of six exec function which one I should use.

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printf("%s",rfile);
if((execv("/usr/bin/od", "/hiren/filem.c"))<0)
perror("exec");
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I was using the aboce code, but it is giving bad address, I am getting
why this error is coming.