i have written a code on assembler... when we enter the mnemonics it will give opcode... when i use %x in the printf it is giving correct opcode.. but when i use %c or %s it is printing some different characters.. but what i want is if i use %s also then it should give correct opcode... how to do this??

It depends on how you've defined the OP Codes and the mnemonics.

i used sprintf.... now when i use %s in printf it is printing correctly on console but when i write that to a txt document usung fwrite its not writing correctly...

it is displaying some unknown characters

C isn't any different from assembly in that there's no magic. The byte representation of an integer isn't going to be meaningful when directly displayed as characters. What *printf() does is convert the value to an string representation along the lines of:

/* Very basic, do not use except as a starting template */
while (value != 0) {
    s[i++] = value % base + '0';
    value /= base;
}

Pretty much the same logic you'd use for the operation in assembly.

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